Object Oriented Programming Through c++

OBJECT ORIENTED PROGRAMMING THROUGH C++ CHAPTER – 1 INTRODUCTION TO OBJECT ORIENTED PROGRAMMING (OOP) INTRODUCTION What is “C++”? C++ is an object oriented programming language. In other words we can say that it is a Hybrid (All features of “C” can be directly implemented with “C++”) programming language or it is superset of “C”. What is the difference between “C” and “C++”? Point “C” Language “C++” Language

Input/Output

Through Library function

Through stream (Object)

BASIC CONCEPTS OF OOPs Object oriented programming language have developed in an evolutionary manner and have become very popular over past few year. C++ is one such language. It is necessary to understand some of the concept of used extensively in OOP. These include: 2. Classes 3. Inheritance 4. Encapsulation 1. Object ADVANTAGE of OOP OOP offers several benefits to the program designer and the user. • Through inheritance, we can eliminate redundant code and extend the use of existing classes.

The principle of data hiding helps the programmer to build secure programs that cannot be invaded by code in other parts of the program. • It is possible to have multiple instances of an object to co-exist without any interference. • It is easy to partition the work in a project based on objects. • It is possible to map objects in the problem domain to those in the program. • Software complexity can be easily managed. COMPARISION OF PROCEDURAL PROGRAMMING AND OOPs When we need to read data item in an object, we call a member functions in the object. The function will access data and return us the value. we cannot access data directly, because data is hidden and cannot be altered accidentally. Data and its functions are said to be encapsulated into a single entity. When we need to modify the data in an object, we need to know the functions that interact with it. Thus we use that function. This procedure simplifies in writing, debugging and maintaining a program. A C++ program thus consists of number of objects which communicate with each other by calling one another’s member functions. DEFINITION OF CLASS AND OBJECT Class: - The concept of class is best understood with an analogy. Class is the way to define/declare the attribute (Instance Variable) and functionality of an object. Object: - An object is the something that has a fixed shape or well defined boundary. In the ordinary sense, an Object is something which is capable of being seen. A object can be any one or all of the following: (a) (a) A vis visib ible le thing thing (b) Something Something that that can be be picked picked up by a person person (c) Something Something towards towards which which thought thought or action action is directe directed d CONCEPT OF INHERITANCE AND ENCAPSULATION Inheritance:-This feature of c++, supports re-usability means that existing class/old class can be extended by a new class. New class is called derived class and old class, on which a new class is created, is called base class. Encapsulation: - It is mechanism that associates the code and the data it manipulates into a single unit and keeps them safe from external interference and misuse. In c++, this is supported by a construct called class. An instance of class is known as an object, which represents a real word entity. OPERATOR OVERLOADING ‘C++’ provides feature to overload mostly arithmetic, relational and other operators. Overloaded means operator can be used in c++ program for addition work not existing task. For example existing function of – (minus) is to negate the digit. But we can use this operator to negate an object (i.e. the additional task of minus operator). Statements to perform additional task, are written under special function namely operator ( ), i.e. provided by c++. Syntax to use operator function: Return type operator (argument) { } DYNAMIC BINDING It means that the code links with program call is not known until the time of call at run time. Dynamic link libraries include predefined functions that are linked with application program when it is loaded dynamically, instead of when executable file is generated statically. It is also known as late binding. BASIC PROGRAM CONSTRUCTION #iinclude int x,y,z; z=x+y; void main() cout<<” enter two integer no.”; cout<<” total is :”<< z<< endl; { cin>>x>>y; } Program statements: - C++ has the following types of program statement: •

NOTES BY –BALJEET SINGH SINWAR

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OBJECT ORIENTED PROGRAMMING THROUGH C++ (i) (i) Decl Declar arat atio ion n sta state teme ment nt (ii) (ii) Assi Assign gnme ment nt stat statem emen entt (iii (iii)) Fun Funct ctio ion n cal calll sta state teme ment nt (iv) (iv) Ret Retur urn n sta state teme ment nt Comments – Comments can be included in a program in three different ways in C++ as given below: Type Usages /* */ */ All ch characters be between /* /* an and */ */ ar are ig ignored. // All characters after the // up to end of the line are ignored.

CHAPTER – 2 ELEMENTS OF C++ LANGUAGE TOKENS & IDENTIFIERS Tokens – Token is the smallest element of a program that is meaningful to the compiler. When we submit a java program to the java compiler, the compiler goes through the text and extracts individual tokens. Tokens can be categorized into the following five types: (a) Identifier (b) Keywords (c) Constants (d) Strings (e) Operators

(a) Identifiers Identifiers: – Identifiers Identifiers refer to the names of variables, variables, functions, functions, arrays etc. given by a programmer. programmer. These are also the names of language objects, which can take many values, one at time. A variable is a name that the program associates with a storage location in memory. The following are the rule to name a Identifier:It can consist of any sequence of letter, digits and underscore (_). The first character should be a letter or an underscore.  No other special characters are allowed. Reserved words (Keyword) cannot be used as name of identifier. It is case sensitive language, so (b) Keywords – The words which are reserved to do specific tasks at time of designing a programming language is known as Keywords. Following are the keywords: auto double int continue for virtual struct break else long default goto catch switch case enum register do if private typedef char extern return asm new try union const float short operator this inline unsigned template static signed throw delete volatile void protected class sizeof friend public while Character set: - There are two character sets in c++ language. These are (a) Source Source characters: characters: - Using source source characters, characters, the source source text is created. created. Example Example - Alphabets Alphabets A to Z and _(undersc _(underscore), ore), Decimals 0 to 9, Special characters + - * ~ # % etc. (b) Execution characters/escape sequences: - These are interpreted at time of execution. The value of execution characters are defined as per the implementation. C++ provides the mechanism to get such characters that are invisible or difficult through execution characters. Execution characters and escape sequences are used inter-changeably. Following are the execution characters: Execution Character Meaning Result at execution time \0 End of string Null \n End of a line Moves the active position to the initial position of the next line. \r Carriage return Moves the active position to the initial position of the next paragraph. \f Form feed Moves the active position to the initial position of the next logical page. \v Vertical tab Moves the active position to the next vertical tabulation position. \t Horizontal tab Moves the active position to the next horizontal tabulation position. \b Backspace Moves the active position to the previous position on the current line. \a Alert Produces an audible alert \\ backslash Presents with a backslash \. VARIABLES AND CONSTANTS Variable: - A variable is a name that our program associated with a storage location in memory. After declaring a variable within a program we can assign it a value. (b) Constants – Constants are refer to fixed values that do not change during the execution of a program. Constants are the following types: (i) Backslash character constant: - The backslash (\) alters the meaning of the character that follows it. Following are the backslash character string and their m eanings:


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OBJECT ORIENTED PROGRAMMING THROUGH C++ Backslash Character \a \b

\f \n

Meaning Produces an audible alert signal. Moves the curser back one space. Moves the cursor to the next page. Print a new line.

Backslash Character \r \t

Meaning Prints a carriage return. Prints a horizontal tab.

\v

Prints a vertical tab.

(ii) Numeric constant constant : - It has a constant numeric value assigned to it. The value of the constant can be positive or negative numeral. There are two types of numeric constant:  Integer Constant: - Integers constant are whole numbers and do not have any fractional or decimal part.  Floating-Point Constant: - The constants, which are used to representing very large or very small numeral values and fractions is known as floating-point constants. (iii) String constant: - A sequence of zero or more characters surrounded by double quotes is called string constant. This can be also defined as an array of character constants. (iv) Symbolic constant: - It is a constant that is represented by name (symbol) in the program. It make a program more readable and protect it from side effects created by variable. In c++, there are two ways of creating symbolic constant:  const: - We can declare a C++ constant by writing const before the identifier’s data type. For example: - const int a = 10;  enum: - An enumerated data types provides a way for attaching names to numbers. In C++, enum automatically enumerates a list of words by assigning them values 0, 1, 2 and so on. For example: height verylarge; Here verylarge is of the type height. Dynamic initialization of variables: variables: - Dynamic initialization is mainly used in OOPL. In C we initialize a variable before using it. But in C++, we can declare and initialize a variable simultaneously at the place where the variable is used for the first time. it means, We initialize a variable at run time. Example: Float average = sum/t; Reference Variables: - A reference variable provides an alternative name (alias) for previously defined variable. Syntax: data-type & ref refer eren ence ce-n -nam amee = vari variab able le-n -nam amee Exam Exampl ples es:: - int int amo amoun untt = 100; 100; int int & tota totall = amou amount nt;; cout cout<< << amou amount nt << tota total; l; DATA TYPES The kind of data that a variable may hold in a programming language is called the data type. There are two reasons for distinguishing among data types. These are: The compiler may use the proper internal representation for each type of the data.  The programmer designing the programs may use proper operators for each type of data.  The data types can be classified into the following three categories: (a) User defined defined data type: type: - User defined defined data type enables enables a programmer programmer to invent invent our data types and define define what values values it can take on. (b) Derived Derived Data Type: - Derived data types types are built from the basic integer integer and floating point data types. types. The array data type is one example of derived data type. (c) Built-in Built-in (Basic) (Basic) Data Types: Types: - The three built-in data data types available available in C++ are: are:  Integral Type – This can be further classified into: int – int is the basic integer data type. It is treated as an integer in that it cannot hold fractional values. char – This is a data type which can hold both the character data or the integer data. For example – char c;  Floating Type – This can be further classified into: float – float integers are not adequate for representing very large values of numbers and fractions. For this we need floating-point types of data representation. double – the word double stands for double precision. It is capable of representing a real number ranging from 1.7x10 308 308 to 1.7x10 hich gives twice as much precision as represented by a float. Void Type – The void data type has two important purposes.  A function does not return a value and the other is to declare a generic pointer. Example – void func (a,b) This informs the compiler that any attempt to use the returned value from func() is a mistake and should be flagged as an error. For example – func (x,y) Array: - Array is the collection of same types of elements with unique name. array allocates contiguous space in memory subscript or index of an array is started with 0 and up to size-1. Array is a data structure (Static). Data structure enables us to store and manipulate organized collection of data. If we have to handle more the one elements elements of same type for common purpose, then we prefer array rather creation of individual variable to store and manipulate data. For Example: int x[3]; Array can be of: • Single Dimension • Double Dimension String: - String is the collection of characters thus we can say that it is example of character array. Declaration of Single Dimension Array: -


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OBJECT ORIENTED PROGRAMMING THROUGH C++

(i)

Syntax: Syntax: Data type [Size] [Size] Declaration of Double Dimension Array: Syntax: Syntax: Data type type Name> [Row][Colum [Row][Column] n] OPERATORS An operator operates on one or more variables and performs an action. It consists of words or symbols. Example: +, -, /, * The Operators can be classified into following categories: (i) Arithmetic tic Op Operator tor (ii) Re Relational Op Operator (iii) ii) Bo Boolea lean Lo Logica ical Op Operator tor (iv) As Assign ignment Op Operator tor Arithmetic Arithmetic Operators: - An arithmetic arithmetic operator is a symbol symbol which performs operations such as addition, addition, subtraction, subtraction, multiplication etc. on numbers n the form of data. Operator Symbol Form Operation Multiplication * x*y x multiplied by y Division / x/y x divided by y Modulus % x%y remainder of x /y Addition + x+y x added by y Subtraction x-y x subtracted by y Increment operator ++ a++ Firstly assign then increment a by 1 ++a Firstly increment by 1 then assign Decrement operator -a-Firstly assign then decrement a by 1 --a Firstly decrement by 1 then assign

(ii)

Relational Operators : - Relational operators are used to compare the values of two variables. Operator Symbol Form Operation Equal to == x==y The result is 1 if value of x is equal to y Greater than > x>y The result is 1 if value of x is greater than y Greator than or equal to >= x>=y The result is 1 if value of x is greater than or equal to y Less than < x
(iii)

Boolean logical Operators : - These operators operate only one Boolean operand, i.e. those operands which have either value 1 (true) or 0 (false). 

(iv)

THE ? OPERATOR - The conditional or ternary-if-else operator (?:) is used for assigning a value to a variable after chec checki king ng a con condi diti tion on.. Syn Synta tax: x: var var = oper operan and1 d1 ? oper operan and2 d2 : ope opera rand nd3; 3; This means: If operand is true Then var = operand2 Else var = operand3 Operator Symbol Operation Logical AND & The result is 1 only if the values of Boolean operands on either side of it are true. Short-circuit AN AND && Same as as lo logical AN AND ex except th that f the le left op operand is is fa false it it wi will no not bother to evaluate the right-hand operand. Logical OR | The result is 1 if any one of the value of Boolean operands is true. Short-circuit OR || Same as logical OR except that if the left operand is true, it considers the result to be true and does not evaluate the right-hand operand. Logical XOR ^ Perform exclusive OR on two operands. Logical NOT ! Inverts the operands. Ternary if-th -then-else lse ?: It is a conditional operator where ? stands for if and : stan tands for else. Assignment Operator : - There are two different categories of assignment operators. These are:  Simple Assignment Operator – The equal to sign (=) is the simple assignment operator. It is of the following form. var = expression;

 Compound Assignment Operator – this operator is a short cut method for assigning values to a variable, when one of the operands is this variable itself. Operator Example Evaluation Operator Example Evaluation += a+=b a=a+b ^ a^b a=a^b -= a-=b a=a-b | a|b a=a|b *= a*=b a=a*b >> a>>b a=a>>b /= a/=b a=a/b >>> a>>>b a=a>>>b %= a%=b a=a%b << a<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ () [] ! ~ ++ -*/% +<< >> >>>

Highest

< <= > >= == != & ^ |

&& || ?: =

Manipulators: - It is data object that used with the insertion and extraction operators. Manipulators are the set of functions which are are used used to mani manipu pula late te the the outpu outputt form format ats. s. The The most most comm common only ly used used mani manipu pula lato tors rs are are endl endl and and setw setw.. Exam Exampl ple: e: cout<<”a=”<> To accept data from keyboard and put in to specified variable. Header File – iostream.h CONDITIONAL STATEMENTS 1. If - else - This control statement is used to check a condition and if the condition returns true then it executed the statements within following braces. If the condition returns false then the statements within braces after else will be executed. Syntax: (Simple if - else) if (Boolean expression) { Statements if expression returns TRUE; } else { Statements if expression returns FALSE; } Syntax: (Nested if - else) if (Boolean expression 1) { if(Boolean expression 2) { Statements if both the above expression returns TRUE; } else { Statements if first expression returns TRUE and second returns FALSE; } } else { if(Boolean expression 3) { Stat Stateement mentss if if fir firsst exp expre ress ssio ion n re return turnss FAL FALSE SE and third hird retu return rnss TRU TRUE; E; } else { Statements if first an and third expression ion both retur turns FA FALSE. SE. } } Syntax: (if - else ladder) if (Boolean expression 1) { Statements if expression 1 returns TRUE; } else if (Boolean expression 2) { Statements if expression 1 returns FALSE but 2 returns TRUE; } . else { Statements if all the above expression returns FALSE. } 2. Switch - case - This control statement is used to select a specific set of instructions to execute among various set of instructions as per input supplied to a single variable. Syntax: switch (variable) { case constant1 : statement1; statement2; break; case constant2 : statement3; statement4; break; . default : statements to execute if all the above conditions are false; } Note: Wr Wron ong g swit switch ch-c -cas asee expr expres essi sion on 1. The case label must not be a floating point number. Case labels should always be integer constants or character constants. 2. The case label must not be a string


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OBJECT ORIENTED PROGRAMMING THROUGH C++ 3. The case label cannot be another identifier but can be a constant identifier. 4. The case label cannot be an expression. LOOP STATEMENT The Loop constructs - The loop or iteration construct, directs a program to perform a set of operation again and again until a specified specified condition condition is achieved. achieved. This condition causes causes the termination termination of the loop. Programming Programming language language C contains contains three statements for looping: 1. The while loop - This loop construct is used to execute the certain set of instructions till the conditions with while command returns true. As soon as the condition becomes false the loop terminated. It is possible that if the condition returns false first time then the loop will terminated without running the enclosed statements even a single time. If someone does not make provision for terminating the loop inside the body of loop then it converted into infinite loop. Syntax: while (Boolean expression returns TRUE or FALSE) SE) { Statements require repeating if the expressions TRUE; } 2. The do...while loop - This loop is used to execute the enclosed statements must for single time, and then check the condition followed by while. If the while returns true then the loop executed again and again. Syntax: do { Statements require to run minimum once and then as per expression; } while (Boolean expression); 3. The for loop - This loop construct is used to execute a set of statements for a given number of times. Thus, it is a shorthand method for executing statements in a loop. Synt Syntax ax:: (a) (a) for( for(in init itia iall cond conditi ition on;; test test cond condit itio ion; n; incr increm emen ente terr or or decr decrem emen enter ter)) { statement1; statement2; } (b) (b) for( for(in init itia ial1 l1,, init initia ial2 l2.. ...; .;te test st1, 1, test2 test2.. .... ..,i ,inc ncr. r./d /dec ecr. r.1, 1, incr. incr./d /dec ecr. r.2 2 ...) ...) { } (c) for(;;) { Body of infinite loop; } 4. The break Statement Statement - If we need to come out of a running program immediately immediately without without letting it to perform any further operation in a loop, then you can use break control statement. 5. The continue statement - This keyword is used to repeat a set of statements again even if the statements contains an error.

6. The goto statement - This unconditional branching statement is used to transfer the control in a program from one point to another point. e.g.

7.

goto label;

. label: statements...; The exit () function - It is defined in the header file and is used to terminate the program execution immediately. It takes the form: exit(status); Where 'status' is the termination value returned by the program and is an integer. Normal termination usually returns 0, while any other number can be used to indicate the error type.

CHAPTER – 3 FUNCTIONS Function Function enables us to break a complex task in to small-small module and each module can be individually called whenever required. Due to such feature complexity of problem can be reduced. Declaration of Function: - The declaration of functions consists of its return type, name and number of arguments. Function declaration is also called unction prototype. It has three main components:  Function name – The function name is any legal identifier followed by the parentheses without any spaces in between.  Function type – The function ‘type’ is the type of the returned value. if the function does not return a value, the type is defined as void.  Arguments – The arguments come inside the parentheses, preceded by their types and separated by commas. Function can be of: • Library Function (System Defined) • User Defined Function: - to implement user defined function in a program, we must have to do the following: Declaration of function – prototype massaging to compile  Definition of function – statement of function for its purpose  Calling of function from required position where the function is required it invokes. Function can be of:1. Function with no argument and no return value. 2. Functi Function on with with argu argumen mentt and and return return value. value. Example: void abc(void); Example: int abc(int,int); 3. Functi Function on with with argu argumen mentt and no no return return valu value. e. 4. Functi Function on witho without ut argum argument ent but retu return rn value value.. Example: void abc(int); Example: int abc(void); A function can be called in two ways: (i) Call by value: - Program to Demonstrate Call by value:


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OBJECT ORIENTED PROGRAMMING THROUGH C++ #include getch( ); #include } void ex exchange(int,int); /*Declarati ratio on of of fu function ion*/ Void exchange(int k,int l) void main( ) { { int m; int a,b; m=k; cout<<”Enter Two Integers”; k=l; cin>>a>>b; l=m; exchange(a,b); cout<<”a=”<>a>>b; *q=t; exchange(&a,&b); cout<<”a=”<<*p< } #include Void sum(int, int) Void sum(int, int); { Void sum(float, float); int z; Void main( ) z=x+y; { int x,y; cout<<”Sum=”<>x>>y; { cout<<”Enter two floating point number”; float m; cin>>k>>l; m=k+l; sum(x,y); cout<<”Sum=”< Xyz( ) #include { Class xyz x=5; { y=55; Private: } Int x,y; Inline int sum( ) Public: {


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OBJECT ORIENTED PROGRAMMING THROUGH C++ return x + y;

} Void main( ) { Xyz xx; xx.show( ); cout<<”Sum=”<
} Void show( ); }; Void xyz :: show( ) { Cout<<”x=”<
CHAPTER – 4 OBJECTS AND CLASSES CLASS AND OBJECTS Class – Class is the way to define/declare the attribute (Data Member) and functionality of an object. Definition of Class – A class is a user defined data type which holds both the data and function. The internal data of a class is called member data and the functions are called member functions. Access Specifier: Private – Data members and member functions are declared under private part cannot be accessed directly through its  object. Public – Data members and member functions are declared under public part can access be directly through its object.  Protected – protected accessibility means that members within a call can be accessed by member functions declared by  that class and any classes “inherited” from that class. Class Declaration: - The class keyword defines a class where all data members are private by default, unless we specify change them using the public or protected keywords. For example: Clas lass kanak /*c /*class declarat ration*/ { int name; /*Private by default*/ } Class Function Definition: - Class functions declared within the lass operate on the data members of the class. We may define a member function within the class declaration or declare it inside the class and define it outside the class. (i) Member Member function definition definition inside inside the class declarat declaration ion – A function function declared declared as a member of a class is called a member function. function. Such functions are normally declared as public in the class definition. The member functions operate upon three data types and accordingly are classified as: Manager Function – The manager functions are used to initialize and lean up the class objects. Constructors and deconstructors  are the two examples of member functions that carry out the manager functions. Accessor Functions – The accessor member functions are the constructor that returns information about an object’s current state.  Implementor Functions – The implementor functions modify the data members and are also called asmutators.  (ii) Member Member Functions Functions – We can declare declare a member member function function in two ways: ways: It is defined on the member function within the class declaration. To define the function within a class, simply add the function  directly to the class. Example – Class point int position() { private: { return x; } int x; int y; } public:  We declare a function inside the lass and define it outside the class. Example: Class point { private: int x; int y; int position() } int int poi point nt :: posi positi tion on() () /*fu /*func ncti tion on posi positi tion on() () belo belong ngss to clas classs poin point* t*// { return x; } (iii) Scope Resolution Operator - C++ supports a mechanism mechanism to access a global variable from a function function in which a local variable is defined with the same name as a global variable. It is achieved using the scope resolution operator. Syntax for accessing a global variable using the scope resolution operator is shown in below :: global variable name Example:#include cout< cout<<” <”lo loca cal= l=”< ”<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ 1. Declar Declarati ation on or definit definition ion of class class 2. Defi Definit nitio ion n of memb member er func functio tion n 3. Defi Definit nitio ion n of of mai main n fun funct ctio ion n Arrays of Objects: - An array is a user defined data type whose members are of the same data type and all the data members are of the same data type and all the data members are stored in adjacent memory locations. Case I => Single Object #include #include Class xyz { private: int a,b; Public: void getdata( ); void putdata( ); }; Void xyz :: getdata( ) { cout<<”Enter Two Integers”; cin>>a>>b;} Void xyz :: putdata( ) { cout<<”a=”< Multiple Object #include { cout<<”Enter Two Integers”; Cin>>a>>b;} #include Void xyz :: putdata( ) Class xyz { cout<<”a=”< Array Type object #include Void xyz :: putdata( ) #include { cout<<”a=”<>a>>b;} Case IV => Pointer type object #include { cout<<”Enter Two Integers”; cin>>a>>b;} #include Void xyz :: putdata( ) Class xyz { cout<<”a=”< => void getdata( ); By name*/ void putdata( ); ptr getd getdat ataa( ); ); ptr ptr  put putda data ta(( ); getc getch( h( ); ); }; } Void xyz :: getdata( ) Object as Function Arguments: - An object may be used as a function just like any other data type. This can be done in one of the following two ways: (i) Pass-by-va Pass-by-value lue - A copy copy of the entire entire object object is passed passed to to the function. function. (ii) Pass-by-re Pass-by-referenc ferencee – Only the address address of the object is transferred transferred to the function. function. When an address of the object is passed, the called function works directly on the actual object used in the call. Returning Objects from Function: - Object an passed as a arguments to a function and function can also return the object. /*Program to demo*/ #include class emp


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OBJECT ORIENTED PROGRAMMING THROUGH C++ {

private:

Cout<< “a “age=”; int number;

int age;

void void getd getdat ata( a())

void void disp displa layd ydat ate( e())

public:

Cin>>age;

} Void displaydate() { cout<< “\n number=”<
}; Void getdata() { cout<< “number=”; Cin>>number; Structure and Classes: - The difference between a structure and class lies in the validity of area of the members. In a class, by default, all members are private while in a structure they are public. Structure: - Collection of different data types of element is called structure. How to declare a structure? Struct ss /*where ss is a tag name, a, b, k, ch are members members of struct ss */ { Int a,b; Float k; Char ch; }aa; /*aa is structure variable of type struct ss*/ /*’struct’ is the keyword to declare/define the structure*/ Structure variable can be of: Single More than one (Multiple) Array type Pointer type

CHAPTER – 5 CONSTRUCTORS AND DECONSTRUCTORS CONSTRUCTORS Basic Constructors: - Constructor is a special member function, which name is similar to their class name. Constructor doesn’t return any value. Constructor can have argument. Constructor cannot be called as normal member function. Constructor is invoked through object instance. Constructor can be of: (i) Defau Default lt Cons Constru tructo ctorr – without without argume argument nt (ii) (ii) Param Paramete eteriz rized ed Constr Construct uctor or – with with basic basic type type argu argumen mentt (iii) Copy Constructor – with user user defined type argument Declaration and Definition: - Following are the main point than can be minded at the time of writing the constructors:  The name of the constructor must be the same as that of its class name. It is declared with no return type (not even void).  It is normally declared in the public access within the lass. Syntax: class user_defined_name { private: Data member; Public: User User_d _def efin ined ed_n _nam ame( e()) //Co //Cons nstr truc ucto torr decl declar arat atio ion n { ___________ } other member functions; }; //end of declaration (i) Default Constructors: Constructors: - This constructor constructor is a special special member function with no arguments which initializes initializes the data members i.e. the default default constructo constructorr accepts accepts no parameters parameters.. /*Program /*Program to demo demo Default Default constr constructor* uctor*// #include }; #include void xyz :: show( ) class xyz { cout<<”a=”< { private: #include int a,b; class xyz public:


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OBJECT ORIENTED PROGRAMMING THROUGH C++ xyz( int x, int y) { a=x; b=y; void show( );

}

void xyz :: show( ) { cout<<”a=”<
}; Overloaded Constructor Demonstration: #include Void show( ); #include }; class xyz Void xyz :: show( ) { private: int a,b; { Cout<<”a=”< Void main() class c1 { c1 obj1(1); //initializing object obj1 with c = 1 { public: int c; c2 ob obj2(2 j2(2); ); //in //init itia iali lizzing ing obje objecct obj obje2 e2 with ith c = 2 c1 (int a) cout< Void show( ); #include }; class xyz Void xyz :: show( ) { private: int a,b; { Cout<<”a=”< } class ABC void display(); { int *roll,*age; }; public: void ABC::display() ABC(int k, int l) { cout<<”roll= ll=”<<*roll; co cout<<”age= ge=”<<*ag *age; } { roll= new int; age= new int; void main() *roll= k; *age= l; { ABCxx(5,7); xx.display(); } DESTRUCTORS It is a special function, i.e. used to release the memory space, i.e. allocated by the object, when object is gone out of scope.  Name of the Destructor is similar to the class, which it belongs. It does not have argument(s) and doesn’t return any value (no return type) Destructor is preceded by ~ (tiled) sign. Basically, Destructor is the feature, i.e. provided by c++. Following points should be kept in mind while defining and writing the syntax for the destructor: • A destructor function must be declared with the same name as that of the class to which it belongs. • The first character of the destructor name must begin with a tilde (~).


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OBJECT ORIENTED PROGRAMMING THROUGH C++ A destructor function is declared with no return types specified (not even void). • A destructor function must have public access in the class declaration. Destructor Demonstration: #include Void show( ); #include }; class xyz Void xyz :: show( ) { private: { cout<<”x=”<
CONSTRAINTS ON CONSTRUCTORS AND DESTRUCTORS Constructors have some special constraints or rules that must be followed while defining them. These are as follows: • Constructors should be declared in the public section. • They do not have return types, not even void and therefore, they cannot return values. • They are invoked automatically when the objects are created. • They make implicit calls to the operators new and delete when memory allocation and cancellation, respectively, are required.

CHAPTER – 6 OPERATOR OVERLOADING ‘C++’ provides feature to overload mostly arithmetic, relational and other operators. Overloaded means operator can be used in c++ program for addition work not existing task. For example existing function of – (minus) is to negate the digit. But we can use this operator to negate an object (i.e. the additional task of minus operator). Statements to perform additional task, are written under special function namely operator( ), i.e. provided by c++. Syntax to use operator function: Return type operator (argument) { } OVERLOADING UNARY OPERATOR Unary operators are operators that act on only one operand, such as increment (++), decrement (--) and the unary minus operators.The following examples illustrate the overloading of Unary Operator: 1. (-) oper operat ator or over overlo load adin ing g #include { X=5; Void xyz :: show() #include Y=10; } { cout<<”x=”< { X=5; Void xyz :: show() #include Y=10; } { cout<<”x=”< { X=5; Void xyz :: show() #include Y=10; } { cout<<”x=”<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ #include }; #include void xyz :: getdata() class xyz { cout<<”Enter va values fo for x and y” y”; ci cin>>x>>y; { private: void putdata() int x, y; { cout<<”x=”< }; #include void xyz :: getdata() class xyz { cout<<”Enter va values fo for x and y” y”; ci cin>>x>>y; { private: void putdata() int x, y; { cout<<”x=”< }; #include void xyz :: getdata() class xyz { cout<<”Enter va values fo for x and y” y”; ci cin>>x>>y; { private: void putdata() int x, y; { cout<<”x=”< }; #include void xyz :: getdata() class xyz { cout<<”Enter va values fo for x and y” y”; ci cin>>x>>y; { private: void putdata() int x, y; { cout<<”x=”< }; #include void xyz :: getdata() Class xyz { cout<<”Enter va values fo for x and y” y”; ci cin>>x>>y; { private: void putdata() int x, y; { cout<<”x=”<) op operator #include class man


}

}

}

}

}

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OBJECT ORIENTED PROGRAMMING THROUGH C++ {

private:

} int age;

public: void getdata(); void operator > (man p) { if (age>p.age) cout<<”Age of aa is greater than age of bb”; else

}; void man :: getdata() { cout<<”enter values for age”; cin>>age; } void main() { Man aa, bb; aa.getdata(); bb.getdata(); aa>bb; }

cout<<”Age of bb is greater than age of aa”; 2. (<) op operator #include class man { private: int age; public: void getdata(); void operator < (man p) { if (age class man { private: int age; public: void getdata(); void operator ==(man p) { if (age==p.age) cout<<”Age of aa is equal to age of bb”; else The following examples illustrate the overloading of Shift Operator: 1. (<< (<<)) oper operato atorr usin using g frie friend nd functi function on #include class xyz { private: int a[3]; public: void getdata(); getdata(); Friend Friend ostream ostream << (ostream, xyz); }; void xyz :: getdata() { for(int i=0;i<3;i++) 2. (>> (>>)) oper operato atorr usin using g frie friend nd functi function on #include class xyz { private: int a[3]; public: void void putdat putdata() a();; Friend Friend istrea istream m << (istre (istream, am, xyz); }; void xyz :: putdata() { for(int i=0;i<3;i++) { cout< class xyz { private: int x, y; public: void getdata(); void putdata();


cout cout<< <<”A ”Age ge of bb is less less than age of aa”; } }; void man :: getdata() { cout<<”enter values for age”; cin>>age; } void main() { Man aa, bb; aa.getdata(); bb.getdata(); aa>age; } void main() { man aa, bb; aa.getdata(); bb.getdata(); aa==bb; }

{ cout<<”Enter th the el element”; ci cin>>a[i]; } } ostream & operator (ostream kout, xyz p) { for(int i=0;i<3;i++) { kout<>xx; xx.putdata(); }

Friend xyz operator + (xyz, xyz); }; void xyz :: getdata() { cout<<”Enter th the el element”; ci cin>>x>>y; } void xyz :: putdata() { cout<<”x=”<
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OBJECT ORIENTED PROGRAMMING THROUGH C++ xyz operator + (xyz p, xyz q) { xyz aa, bb, cc; aa.getdata() a(); bb bb.getdata(); { xyz t; t.x = p.x+q.x; cc = aa + bb; aa.putdata(); bb.putdata(); t.y = p.y+q.y; return t; cc.putdata(); } } void main() Examples of Arithmetic overloading Addition of Polar co-ordinates: #include temp.x=x+obj.x; class coordinate temp.y=y+obj.y; return temp; { int x,y; } public: }; coordinate(int i, int j) void main() { x=i; y=j; } { coordinate A(3,4), B(7,10); coordinate operator +(coordinate obj) coordinate C=A+B; { coordinate temp(0, 0); } Concatenation of String: #include }; #include void String :: display() class String { cout<
CHAPTER – 7 DERIVED CLASS AND INHERITANCE DERIVED CLASS AND BASE CLASS A base class is a class from which other classes are derived. And a derived class can inherit members from a base class. DERIVED CLASS CONSTRUCTORS When a derived class object is created, we have to supply values that are required by the derived class as well as by the base class. Inside a derived class constructor, the base constructor(s) is executed first before executing the statements in the body of the derived constructor. The general form a derived class constructor is the following: Derived_class_name (arg1, arg2, ….., argn); Base_class_name (arg1, arg2, …..); { //body of the derived class } OVERRIDING THE MEMBER FUNCTIONS When a derived class implements a function that has the same name as well as the same set of arguments as the function in the base class, it is called function overriding. /*Program to demo function overriding*/ #include void print() class SuperA { cout<< “I am derived class’s function ion\n”; { public: SuperA :: print(); void print() } { cout<< “I am a Base class’s function\n”; } }; }; void main() class SubA : public SuperA { SubA a; a.print(); } { public: INHERITANCE This feature of c++, supports re-usability means that existing class/old class can be extended by a new class. New class is called derived class and old class, on which a new class is created, is called base class. There are following types of inheritance: Sing Single le Inhe Inheri rita tan nce (ii) (ii) Mult Multip iple le Inhe Inheri rita tanc ncee (iii (iii)) Mult Multil ileevel vel Inhe Inheri rita tanc ncee (iv) (iv) Hie Hierarc rarchi hica call Inhe Inheri rita tanc ncee (v) (v) Hybri ybrid d (i) Inheritance In heritance ce: - A derived class has only onl y one base class. (i) Single Inheritan Synt Syntax ax:: clas class< s: >: s> > Case I – If the association between base and derived class is public:


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OBJECT ORIENTED PROGRAMMING THROUGH C++ #include Class base { protected: int a, b, c; public: void get1(); void put1(); }; class derived : public base { int e, f; public: void get2(); void put2(); }; void base :: get1() Case II – If the association between base and derived class is private: #include class base { protected: int a, b, c; public: void get1(); void put1(); }; class derived : private base { int e, f; public: void get2(); void put2(); }; (ii) Multiple Multiple Inheritance Inheritance:: - A derived derived class more than than one base classes. classes. #include

{ cout<< cout<<”En ”Enter ter the elemen element”; t”; cin>> cin>>a>> a>>b>> b>>c; c; } void base :: put1() { cout<< cout<<”a= ”a=”<< ”<> cin>>e> e>>f >f;; } void derived :: put2() { cout cout<< <<”e ”e=” =”<< <> cin>>a>> a>>b>> b>>c;} c;} void base :: put1() { cout<< cout<<”a= ”a=”<< ”<> cin>>e> e>>f >f;; } void derived :: put2() { cout cout<< <<”e ”e=” =”<< <
}; void xyz :: getdata() class xyz { cout cout<< <<”E ”Ent nter er the the elem elemen ent” t”;; cin>> cin>>x> x>>y >y;; } { protected: void xyz :: putdata() int x, y; { cout cout<< <<”x ”x=” =”<< <> cin>>a> a>>b >b;; } }; void abc :: putdata1() class abc { cout cout<< <<”a ”a=” =”<< <> cin>>k> k>>b >b;; } public: void kbc :: putdata2() void getdata1(); void putdata1(); { cout cout<< <<”k ”k=” =”<< < void get3(); void put3(); class a }; { protected: void a :: get1() int aa; { cout cout<< <<”E ”Ent nter er the the elem elemen ent” t”;; cin> cin>>a >aa; a; } public: void a :: put1() void get1(); void put1(); { cout<<”aa=”< cin>>b >bb; b; } { protected: void b :: put2() int bb; { cout<<”bb=”< cin>>c >cc; c; } }; void c ::put3() class c : public b { cout<<”cc=”<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ yy.put1(); yy.put2(); yy.put3(); } (iv) Hybrid Inheritance: - An inheritance inheritance has characteristics characteristics of more than one inheritance, called Hybrid inheritance. #include } class a void a :: get1() { protected: { cout cout<< <<”E ”Ent nter er the the elem elemen ent” t”;; cin>> cin>>x> x>>y >y;; } int x, y; void a :: put1() public: { cout cout<< <<”x ”x=” =”<< <> cin>>a> a>>b >b;; } class b: public a void b :: put2() { protected: { cout cout<< <<”a ”a=” =”<< <> cin>>p> p>>q >q;; } void get2(); void put2(); void d :: put3() }; { cout cout<< <<”p ”p=” =”<< <> cin>>k> k>>b >b;; int p, q; } public: void c :: put4() void get3(); void put3(); { cout cout<< <<”k ”k=” =”<< <
CHAPTER – 8 POINTERS ADDRESSES AND POINTERS A Pointer is a variable that holds the address of the location of another variable in the main memory of the computer. A pointer provides a way of accessing a variable without referring to the variable directly. Pointers are used when passing actual values is difficult or undesirable. Some reasons to use pointers are as follows: • To return more than one value from a function. • To pass arrays and string more conveniently from one function to another. • To manipulate arrays more easily by moving pointers to them, instead of moving the arrays themselves. • To create complex data structures, such as linked lists and binary trees where one data item must contain references to other data items. • To communicate information about memory as in the function delete() which returns the location of free memory by using a pointer. Address of Operator (&) and Pointer Variables: - The operator ‘&’ is used to get the address f a variable. Program to demo the use of &. #include main() { int x; x=2; cout<< “\naddress of memory location for x”< main() { int x; x=2; cout<< “\nvalue stored at address”<<&x<<”is”<<*(&x)<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ #include cout< void main() void display(char *ptr) { char *str[6] = “I am a Stri tring”; display(str); { cout< for(int i=0; I,6; i++) void main() { cout< void main() { int *ptr_x = new in int; int *p *ptr_y = new int; int *ptr_mul = new int; int *ptr_div = new int; cout<< “\nType any two integers”<>*ptr_x>>*ptr_y; *ptr_mul = (*ptr_x) * (*ptr_y); *ptr_div = *ptr_x/*ptr_y; cout<< “Product of (*ptr_x and *ptr_y) =”<<*ptr_mul<) sign. sign. Syntax Syntax:: object object_na _name me  member_name = variable; This operator: - C++ uses a pointer called this to represent the object that invoked the member function. In other words we can say that this is a pointer that points to the object for which the member function was called. POINTERS TO POINTERS A pointer to a pointer is a construct used frequently in more complex programs. To declare a pointer to a pointer, place the variable name after two successive asterisks (*). For instance int **z; declares z to be a pointer to an integer variable z.

CHAPTER – 9 VIRTUAL FUNCTIONS POLYMORPHISM It includes the ability to use the same message to objects of different classes and make them behave differently. Thus we could define “+” for both the addition of numbers and the concatenation of characters, even through both these operations are completely different, thus, polymorphism provides the ability to use the same word to invoke different methods/action according to similarity of meaning. It allows the programmer to define a base class that includes routines that perform standard operations on groups of related objects, without regard to the exact type of each object. There are two types:

1. Comp Compil ilee time time poly polymo morp rphi hism sm: - The The over overlo load aded ed member member functi functions ons are “selec “selected ted for invoki invoking” ng” by matching the member of arguments and argumentstype. This information, viz. number of arguments types is known to the compiler at the compile time itself.


28

OBJECT ORIENTED PROGRAMMING THROUGH C++ 2.

Therefore, the selection of the appropriate function made the compile time only. This is known as early binding or static binding. Run time polymorphis polymorphism m: - In run time polymorphis polymorphism, m, function function is blind with their object object at runtime not compile time. So that appropriate version of the function can be called run time polymorphism. It is also known as late binding.

VIRTUAL FUNCTION C++ use to use same function in different levels of class hierarchy. But we have to make function virtual function is the implementation of run time polymorphism. In run time polymorphism function is bin with their object at run time not compiling time. Program to achieve Run Time polymorphism/Late binding/Demo. Of virtual function #include { cout<<”Enter th the va value fo for x and y” y”; ci cin>>x>>y; } class xyz void xyz :: putdata() { protected: { cout<<”x=”< >>a>>b; } virtual void getdata(); virtual void putdata(); void abc :: putdata() }; { cout<<”a=”< abc() class xyz { A=5; B=10; } { Public: void display(); Virtual void display() = 0; }; }; void abc :: display() class abc : public xyz { cout<<”a=”< void abc :: putdata() class abc { cout<<”c=”<
Output: C=0

C=0

C=0

C=3

C=3

C=3

invoked with class Static Member Function: -  Static Member function can access the static member.  Static member function is invoked name as: Class name :: function name() We know that static member is declared under class but it is not the part of any object. That’s why it needs to declare outside the class also as: datatype class name :: static member #include void abc :: putdata() class abc { Cout<<”c=”<

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OBJECT ORIENTED PROGRAMMING THROUGH C++  Friend function can be friend of one class and more than one class.

Friend Function Demonstration: - Example (1): #include class xyz #include { private: int x,y; class xyz public: { private: int a,b; void getxyz( ); void putxyz( ); public: friend void sum(xyz,abc); void getdata( ); void putdata( ); }; friend void sum(abc); void xyz :: getxyz( ) }; { cout<<”Enter Tw Two In Integers”; ci cin>>x>>y; } void xyz :: getdata( ) void xyz :: putxyz( ) { cout<<”Enter ter Two Two Integers”; cin>>a>>b; } { cout<<”x=”<>a>>b; } void sum(abc xx) void abc :: putabc( ) { int z; z=xx.a+xx.b; { cout<<”a=”< ll.putabc( ); sum(cc,ll); getch( ); #include } class abc; MACROS AND INLINE FUNCTION Macros: - The preprocessor directive #define can be used to create macro functions. A macro function is a symbol created using #define and that takes an argument, much like a function does. The preprocessor will substitute the definition string for whatever argument it is given. For example: #define TWICE(x) ((x) * 2) and then in our ode we write TWICE(2). Comparison between Macros and Inline Function: • Macros can be confusing if they get large, because all macros must be defined on one line. • Macros are not type safe. Any argument can be used with a macro, while this is not possible with inline functions which does strong typing.

CHAPTER – 10 STREAMS STREAM CLASSES C++ uses the following classes to implement streams: • ios class: - This is the base class to the input and output stream classes. • istream and ostream classes: - These are derived class from the ios class and and poss posses es spec specia ializ lized ed inpu inputt and and output stream behaviour, resp respec ecti tive vely ly.. The The istr istrea eam m clas classs cont contai ain n such such func functi tion onss as get( get(), ), getline() and read() while the stream class ontain such functions as put() and write(). • iostream class: - This is derived from bot both h the the istr istrea eam m and and the the ostr ostrea eam m classes and provides input and output functions for reading from the keyboard and writing to the monitor. • fstream classes: - These classes provide input and output from files. The ifstream class is used for creating input file, ofstream class for output file and fstream for files that will be used for both input and output. These classes are derived from istream, ostrem, iostream and from fstreambase. STREAM CLASS HIERARCHY HEADER FILES A header file provides a centralized location for the declaration of all extern variables, function prototypes etc. program files that must use or define a variable or a function must include the corresponding header files. For example, for using I/O functions, we need to include iostream.h file at the beginning of a program. The header file “ fstream.h” provides support for simultaneous I/O operations. It contains the classes ifstream and ofstream that provide I/O operations.


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OBJECT ORIENTED PROGRAMMING THROUGH C++ ios FLAGS C++ provides several methods for formatting the output. These are the following: Functions and flag defined in the ios class.  Manipulators.  User-defined output functions. The ios class defines formatting flags and error-status flags. Some of the following formatting flags are as follows: Skipws: - Skip whitespace on input.  Left – left-adjusted output.  Right – right-adjusted output.  Dec – convert to decimal.  Oct – convert to octal.  Hex-convert to hexadecimal.  Showos –display + before positive integers.  Stdio – flush stdout, stderror after insertion.  Scientific – print floating point number in scientific notation. Following are the error flags:  goodbit – no errors. eofbit – reached end of file.  failbit – operation failed.  badbit – invalid operation. hardfail – unrecoverable error. STREAM MANIPULATORS Stream Manipulators are the following-instructions which are inserted directly into a stream. These can be used to set the formatting and displaying characteristics and other attributes of the stream objects. Come important manipulators are as follows:  ws – turn on whitespace.  ends – insert null character to terminate an output string.  flush – flush the output stream.  dec – convert to decimal.  oct – convert to octal.  hex – convert to hexadecimal.  setw (int field-width) field-width) – set field width for output. output.  setfill(int fill-character) – set fill character for output. set precision(int precision) – set preision.  setiosflags(long formatting-flags) – set the specified flags.  resetiosflags(long formatting-flags) – reset the specified flags. STRING STREAMS The program that read and write strings from/to disk files, is given below: #include void main() { ofstr fstrea eam m file file_o _out ut(“ (“te test st.t .txt xt””); //c //cre reat atee fil filee for for out outpu putt file_out<< “This string will go into the file test.txt”; char arr[80]; file_o file_out. ut.clo close( se(); ); //clos //closee the the file file ifstream file_in(“test.txt”); //create file for input file file_in _in.g .get etli line ne (ar (arr, r, 80); 80); //rea //read d a line line of tex textt cout<>a; output< char ch[n]; ifstream input (“xyz”); #include while (input) #include { input.getline (ch, n); void main() cout< void main() #include { ofstream kk kk; kk.open (“City”); #include kk<<”Patna”; kk<<”Ranchi”; kk<<”Kolkata”;


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OBJECT ORIENTED PROGRAMMING THROUGH C++ kk<<”Delhi”; kk<<”Mumbai”; kk.close(); { ll.getline (ch, n); cout< { ff.put(nm[i]); } #include ff.s ff.see eekg kg(0 (0); ); /*To /*To rese resett the the get get poin pointe terr at begi beginn nnin ing g void main() of file*/ { char nm nm[15]; co cout<<”Enter th the st string”; char ch; cin>>nm; int length = strlen(nm); { ff.get(ch); cout< cout<<”Designation”< cout<<”Employee salary”<>empno; ff.write((char*) & ee[i], size of (ee[i])); cout<<”Enter salary”; cin>>sal; } cout<<”Enter Designation”; cin>>design; for(i=0;i<10;i++) cout<<”Enter employee name”; cin>>name; { ff.read((ch (char*) & ee[i], size ize of (ee[i])) ])); } ee[i].putdata(); void emp :: putdata() } { cout<<”Employee Name”<KBC odd Even int i; ofstream ff, ff’; ff.open(“argv[1]”,ios::out); Name of source file(c++ file name) ff’.open(“argv[2]”,ios::out); void main(int argc, char *argv[]) if(argc!=3) { { exit(0) } argv[0]=KBC for(j=0;j<6;j++) argv[1]=odd { if(a[j]%2==0) argv[2]=Even


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OBJECT ORIENTED PROGRAMMING THROUGH C++ ff<
} ffclose(); ff’close();

else ff’<
}

CHAPTER – 11 EXCEPTION HANDLING Exception handling provides a way of transferring control and information to an unspecified caller that has expressed willingness to handle exceptions of a given type. Exception of arbitrary types can be ‘throw and catch ‘and set of exceptions a function may throw can be specified. Exception handling handles run time errors. Mainly generated the run time errors are as follows:logical:- poor understanding of given problem and procedure of solution. Syntax :- poor understanding of programming language. Exception:- arises when program executed due to: Illegal arithmetic expression like digit divided by zero.  Array overflow.  Array index out of bound.  Incompatible assignment etc. It mechanism transfers control and information from a point of exception in a program to an exception handler associated with the try block. An exception handler will invoked only by a thrown expression in the code executed by the handler’s try-block. C++ provides following keywords to deal with exception. These are:Try: - try is basically, a block where exception is generated. Throw: - when exception is generated, it must be ‘throw’ is used to throw the exception. ‘throw’ is used in ‘try’ block. Catch: - catch () is also a block, where exception handler statements are defined. It is basically a function & accepts exception that is thrown by throw. # program to demo. Exception handling void main() { int b,c; cout<<”enter value of b & c”; c”; cin>>b>>c; try{ if(c==0) throw c; else cout<>n; test(n); catch(char nm) } { cout<<”exception caught”<
CHAPTER – 12 CLASS LIBRARIES Class Libraries : - C++ provides a library of data structures. Standard C++ includes its own built-in container class library. String Class: - The string class stores the string as a character array and it includes a field that stores the size of the array. In order to use this this clas classs we we need need to to place place the statem statement ent:: #inclu #include< de > Constructors String() It creates an empty class. Syntax: string s1; String s2(“kanak” s2(“kanak”)) Initialize Initialize the string with a charac character ter array. array. Stri String ng s1(s s1(s2) 2) Init Initia iali lize ze a str strin ing g (sa (say y s1) s1) from from anot anothe herr str strin ing g (sa (say y s2) s2) using using the stat statem emen entt String String s1(6 s1(6,, ‘m’) ‘m’) Initia Initializ lizee a string string as as a repeat repeated ed seque sequence nce of of charac character terss using using the the statem statement ent Function


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OBJECT ORIENTED PROGRAMMING THROUGH C++ Assi Assign gn() () To rese resett a stri string ng’s ’s valu values es base based d on a subs substr trin ing g of anot anothe herr str strin ing. g. Synt Syntax ax:: s1.a s1.ass ssig ign( n(s2 s2,1 ,1,2 ,2); ); Insert() To in insert a string in inside an another. Sy Syntax: s1 s1.insert(2, “v “vinod”); Resize() To ch change th the size of of st string. Sy Syntax: s1 s1.resize(20); Length() To de determine th the cu current le length of st string. Sy Syntax tax: in int le len = s1.length(); Find() To search a string for the position at which a substring starts. Stack Class: - The stack class operates much like the standard stacks. It is implemented as a template class, so we can make a stack a stack obje object ct of any any dat dataa typ type. e. In orde orderr to to use use this this clas classs we we nee need d to to plac placee the the stat statem emen ent: t: #incl #includ ude< e k>;; Program to demo: #include #include int main() cout< > s; //Make a stack stack using using a vector vector s.pop(); container cout< Member Function Bool empty() Returns true if size is zero List_type back() Returns a copy of the back element List_type front() Returns a copy of the front element Void merge(anotherlist) Merges in the contents of another list Void pop_front(element) Removes the front element Void push_front(element) Adds an element at the front Void push_rear(element) Adds an element at the back Void remove(element) Removes ALL occurrences of the element Void reverse() Reverses the order of the list Int size() Gets the current number of lists element Void sort() Sorts the list elements (ascending order) Void swap(anotherlist) Swaps this list’s contents with the other list Queue Class: - This is also a template class. It includes the member functions discussed in the following sections. In order to use this class we need to place #include Member Function Queue_type back() Returns the item at the back of the queue. Bool empty() Returns true if the queue is empty, otherwise false Queue_type front() Returns the item at the front of the queue. Void pop () Removes the item at the front of the queue Void push (queue_type x)) Pushes x onto the back of the queue. Int size() Returns the number of elements on the queue Microsoft Foundation Classes (MFC): - MFC is an extensive C++ class library designed for creating Windows GUI programs. The MFC simplifies writing these programs, and it provides many high-level features that can save our time for coding effort.

CHAPTER – 13 ADVANCE CLASSES TEMPLATES Template is an advance feature in C++ that allows a single function or class to handle more than one data types. Generic Function: - There may be times when we duplicate a function just because we wanted it to support parameters of a different data type. For example, the following function compare(), compares two values of type int and returns the larger value: int compare (int a, int b) else { if (a>b) return b; return a; } If the two functi functions ons appear appear in the same same progra program, m, we must search search for a differe different nt name name for each of the functio functions. ns. Such complications are reduced by usages of templates of templates.. Thus, using templates, we can create generic functions. A Generic function is a function that could be used to work on different argument type.


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OBJECT ORIENTED PROGRAMMING THROUGH C++ Generic Class: - Templates allow us to define generic classes. A generic class is a class that can be used with any data type. Parameterized templates give us the ability to create a general class, and pass data-type as parameter to that class, in order to build specific instances. Template Class: - Template is the latest features of c++. Template enables us to define generic function & generic class and provide facilities for generic programming. In generic programming parameters are generic means that parameters can be used for any data types. Program to demo. class templates template void xyz::display() class xyz { cout<<”a=”<aa(5,7); { a=x; b=y; xyzbb(13.2,15.7); } aa.display; bb.display; void display(); } }; Program to demo class templates with two parameters templates void xyz::display() class xyz { cout<<”a=”<aa(5,7.3); { a=x; b=y; xyzbb(6,’v’); } aa.display(); bb.display(); void display(); } }; Program to demo. function template template template void exchange(t x,t y) void sum(t1 x,t2 y) { t z; z=x; x=y; y=z; { t2 z; z=x+y; cout<<”x=”<>a>>b; exchange(a,b); cin>>a; cout<<”Enter float”; cout<<”Enter two floats”; cin>>b; sum(a,b); cin>>j>>k; exchange(j,k); } } Member function template template { cout<<”Enter two numbers”; class xyz cin>>a>>b; { t a,b; }template public: void xyz::putdata() void getdata(); void putdata(); { cout<<”a=”< { xyz pp; pp.getdata(); pp.putdata(); } void xyz::getdata() Temp Templa late te Func Functi tion on:: - A te templa mplate te func functi tion on is dec declare lared d as as fol follo lows ws:: temp templa late te T> void void func functi tion on-n -nam amee (T (T a); a); The function is declared to be a Template Function by the declaration on the top line. o Template function can have any name, just as other functions can. o Template function can also take objects of instances of a template class as arguments. o Template function can be an array of anu data type. o Example – template else T compare (T a, T b) return b; { if (a>b) } return a; Overriding of Generic Functions: - If we want that a particular template function should behave differently with a particular data type, say int. this is possible using function overriding. For this, we simply define a normal C++ function that has the same name as the function template but uses specific fixed data types rather than template types. This function will override the function template i.e. if we pass parameters of the types specified in the normal function, the compiler will call this function rather than generating a function based on the template. Program to demo: #include Template


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OBJECT ORIENTED PROGRAMMING THROUGH C++ void print (T a) Float y = 10.56; { cout<<”all data types\n”; } Print(x); //function called with int data type void print int(float a) //o //overriding template fun function Print (y (y); //function ca called wi with fl float da data ty type { cout<<”float data type\n”; } Print (“Hello”); (“Hello”); //function //function called called with with string string data type Void main() } { int x = 10; Containers and Nested Class: - A container class is a class that operates on a collection of zero or more objects of a particular type. The use of template facility in defining container classes, will allow us to define a single class that can work for all data types. For example, we can define an object of container class Vector. then, this object will contain a vector of integer values. Program to demo Container class: #include { size = m; v = new T[size]; Template } Class Vector Vect Vector or (T *a) *a) //cr //crea eate te a vect vector or from from an arra array y { T *v; //type T vector { for(int i=0; i }; Class ChList ChNode *head; { Protected: Public: Clas Classs ChNo ChNode de //Hid //Hidde den, n, pro prote tect cted ed nod nodee clas classs ChList(); ~ChList(); int AddtoFront (char &c); { public: int RmvHead (char &c); int IsEmpty(); int IsFull(); Char data; ChNode *next; ChNode(); }; Objective Question (1) A c++ operands must start with a lower character. (2) A return statement in a function transfer control from the function to the point of its invocation. (3) All pre-process directives must start with # sign. (4) Counting of elements in a c++ array starts from zero. (5) A character string must be terminated with a NULL character. (6) The non-member function accesses the data member of a class called friend function. (7) The #define directory is used to define symbolic constants. (8) A special function namely catch is used to catch the exception that is thrown by throw. (9) Constructor is used to initiate the object with instance. (10) A function namely destructor releases the memory i.e. occupied by an object, when gone out of scope. Access voiletion class xyz void get2(); voidput2(); { int a,b; }; protected: void main() int x,y; { public: ABC xx; -------(i) xx.a=15;-------(ii) int z; void get1(); void put1(); xx.z=13;-------(iii) xx.put1();------(iv) }; xx.y=21;-------(v) xx.J=25;-------(vi) class ABC:public xyz xx.put2();------(vii) { int J,K; } public: (v) y is a protected data member of base class xyz. so it cannot be access directly by the object of its derived class. (ii) It is a private data member of base class xyz and cannot be accessed even their own object. (vi) Same reason as describe in(ii). Class Libraries c++ provides string class to implement all the features associated with string. #include Constructor :--> (ii) string s1; we can declare string object/string(empty)using default constructor. (iii) (iii) Initia Initializ lizee the the string string with with a char charact acter er arra array. y. string s2(“Polytechnic”); (iv) (iv) Initi Initial aliz izee strin string g with with anoth another er stri string ng.. string s1(s2);


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OBJECT ORIENTED PROGRAMMING THROUGH C++ (v)

Initia Initializ lizee a stri string ng with with repeat repeated ed sequ sequenc encee of char charact acters ers.. string s1(6,’A’); Overloaded operator :--> (i) The As Assignment op operator(=) ------Lopies the string on the right side into the string on } the left side of the operator =. else Example--> string s1,s2; { s2=”ABC” -----s1=s2 } (ii) Comparison operator(<, (<,<=,>, ,>,>=) >=) (iii (iii)) Addi Additi tion on oper operat ator or(+ (+)) for for conc concat aten enat atio ion n Example--> string s1,s2; Example--> string s 1,s2,s3; s1=”ABC”; s1=”XYZ”; s2=”KBC”; s2=”PVT Ltd”; if(s1 #include member functions:(i) (i) bool bool emp empty ty() () :-:--> > This This mem membe berr func functio tion n retu return rnss true true if if the the siz sizee of list list is zero zero.. (ii) (ii) void void pop pop_f _fro ront( nt()) :--> :--> This This mem membe berr func functi tion on is is used used to to dele delete te the the fro front nt ele eleme ment nt.. (iii) (iii) void void push_f push_fron ront(e t(elem lement ent)) :--> :--> This This membe memberr functi function on is used used to add add the the eleme element nt in fron front. t. (iv) (iv) void void push push_re _rear(e ar(elem lement ent)) :--> :--> This member member functi function on adds adds the the elemen elementt at at rear rear.. (v) void void remo remove( ve(ele element ment)) :--> :--> This This memb member er functi function on remo removes ves all occurre occurrence ncess of of elem element ents. s. (vi) (vi) void void reve revers rse( e()) :--> :--> This This memb member er func functi tion on reve revers rsee the the lis list. t. (vii) (vii) void void sort() sort() :--> :--> This This membe memberr functi function on arran arranges ges the the elemen elements ts in the the ascen ascendin ding g order. order. Stack class --> #include member functions:(i) (i) bool bool empty mpty() () :--> :--> retu return rnss tru truee if if sta stack ck is empty mpty.. (ii) (ii) void void pop( pop()) :--> :--> remo remove vess the the item item from from top top of the the stac stack. k. (iii) (iii) void void pus push( h(el elem emen ent) t) :--> :--> add addss the the item item at at the the top top of the the sta stack ck.. (iv) (iv) int int siz size( e()) :--> :--> retu return rnss tot total al numb number er of elem elemen entt in in a stac stack. k. Pointer --> Pointer is a special variable that can hold the address of another variable of same type. Pointer is associated with address. Using pointer, several features of c and c++ become easy/efficient to handle. Pointer provides another ways to work with a variable or function. We have to handle a variable with pointer then we must have to assign its base address to pointer. Variable- Variable is the popular element of programming language which is used to stored related types of data. Declaration of pointer :while(i<6) Datatype *pointer variable; { cout<<*ptr; Example  ptr++; int *ptr, a; i++; a=15; } ptr=&a; String--> best example of Array(character) cout<<*ptr; *If we have to work with string ,then we use character array Array handling through pointer :to hold and manipulate the string. int s[6] ={1,3,5,7,2,4}; Example- char *string 1=”How many bytes are allocated for int*ptr,1; short int”; ptr=&s[0]; cout<

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OBJECT ORIENTED PROGRAMMING THROUGH C++ New operator  New operator is used to create exactly needed memory space at runtime for specified type. In c this operation is performed by a function namely malloc(). When our program is compiled it is broken into four parts. i.e. program code ,global data, stack and heap(free memory area). Example- int *p=new int; *p=5; Delete operator It is mainly used to releases the memory area. i.e. allocated by new operator. It is just like free() function of c. Example- delete p; Int *p= new int; *p=5; Delete p;


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Object Oriented Programming Through c++

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