CS8251 Programming in C-question Bank With Answer Keys

Programming in C

CS8251

Ms. A.Mary JaNiS, Assistant Professor/CSE, Alpha College of Engineering

PROGRAMMING IN C

LTPC3003

SYLLABUS OBJECTIVES: 

To develop C Programs using basic programming p rogramming constructs



To develop C programs using arrays and strings



To develop applications in C using functions , pointers and structures



To do input/output and file handling in C

UNIT I BASICS OF C PROGRAMMING

9

Introduction to programming paradigms - Structure of C program - C programming: Data Types – Storage Storage classes - Constants – Constants – Enumeration Enumeration Constants - Keywords – Keywords – Operators: Operators: Precedence and Associativity - Expressions - Input/Output statements, Assignment statements – statements – Decision Decision making statements - Switch statement - Looping statements – Pre-processor directives - Compilation process UNIT II ARRAYS AND STRINGS

9

Introduction to Arrays: Declaration, Initialization – Initialization – One One dimensional array – array – Example Example Program: Computing Mean, Median and Mode - Two dimensional arrays – Example Program: Matrix Operations (Addition, Scaling, Determinant and Transpose) - String operations: length, compare, concatenate, copy – copy – Selection Selection sort, linear and binary search UNIT III FUNCTIONS AND POINTERS

9

Introduction to functions: Function prototype, function definition, function call, Built-in functions (string functions, math functions) – Recursion – Example Program: Computation of Sine series, Scientific calculator using built-in functions, Binary Search using recursive functions – Pointers Pointers – Pointer Pointer operators – Pointer Pointer arithmetic – arithmetic – Arrays Arrays and pointers – pointers – Array Array of pointers – Example Program: Sorting of names – Parameter passing: Pass by value, Pass by reference – Example Program: Swapping of two numbers and changing the value of a variable using pass by reference UNIT IV STRUCTURES

9

Structure - Nested structures – structures – Pointer Pointer and Structures – Structures – Array Array of structures – structures – Example Example Program using structures and pointers – pointers – Self Self referential structures – structures – Dynamic Dynamic memory allocation - Singly linked list - typedef 1

Programming in C


UNIT V FILE PROCESSING

9

Files – Types of file processing: Sequential access, Random access – Sequential access file Example Program: Finding average of numbers stored in sequential access file - Random access file - Example Program: Transaction processing using random access files – Command line arguments OUTCOMES: Upon completion of the course, the students will be able to 

Develop simple applications in C using basic constructs



Design and implement applications using arrays and strings



Develop and implement applications in C using u sing functions and pointers.



Develop applications in C using structures.



Design applications using sequential and random access file processing.

TEXT BOOKS:

T1. Reema Thareja, ―Programming in C‖, Oxford University Press, Second Edition, 2016. T2. Kernighan, B.W and Ritchie,D.M, ―The C Programming language‖, Second Edition, Pearson Education, 2006 REFERENCES:

R 1. 1. Paul Deitel and Harvey Deitel, ―C How to Program‖, Seventh edition, Pearson P earson Publication R 2. 2. Juneja, B. L and Anita Seth, ―Programming in C‖, CENGAGE Learning India pvt. Ltd., 2011 R 3. 3. Pradip Dey, Manas Ghosh, ―Fundamentals of Computing and Programming in C‖, First Edition, Oxford University Press, 2009. R 4. 4. Anita Goel and Ajay Mittal, ―Computer Fundamentals and Programming in C‖, Dorling Kindersley (India) Pvt. Ltd., Pearson Education in South Asia, 2011. R5. Byron S. Gottfried, "Schaum's Outline of Theory and Problems of Programming with C",McGraw-Hill Education, 1996.

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Programming in C


UNIT - I BASICS OF C PROGRAMMING

PART - A 1. Define compiler.

It is a program used to convert the high level language program into machine language. 2. What are the types of programming language?

· Machine language · Assembly language · High level language 3. What are the different data types available in „C‟?

There are four basic data types available in „C‟. 1. int 2. float 3. char 4. Double 4. What are Keywords?

Keywords are certain reserved words that have standard and pre-defined pre-defined meaning in„C‟. These keywords can be used only for their intended purpose. 5. What is an Operator and Operand?

An operator is a symbol that specifies an operation to be performed on operands. Example: *, +, -, / are called arithmetic operators.

The data items that operators act upon are called operands. Example: a+b; In this statement a and b are called operands. 6. What is Ternary operators or Conditional operators?

Ternary operators is a conditional operator with symbols ? and : Syntax: variable = exp1 ? exp2 : exp3

If the exp1 is true variable takes value of o f exp2. If the exp2 is false, variable takes the value of exp3. 7. What are the Bitwise operators available in „C‟ ?

& - Bitwise AND | - Bitwise OR 3

Programming in C


~ - One‟s Complement >> - Right shift << - Left shift ^ - Bitwise XOR are called bit field operators 8. What are the logical operators available in „C‟?

The logical operators available in „C‟ are && - Logical AND || - Logical OR ! - Logical NOT 9. What is the difference between Logical AND and Bitwise AND?

Logical AND (&&): Only used in conjunction with two expressions, to test more than one condition. If both the conditions are true the returns 1. If false then return0.AND (&): Only used in Bitwise manipulation. It is a unary operator. 10. What is the difference between „=‟ and „==‟ operator?

Where

=

is

an

assignment

operator

and

==

is

a

relational

operator.

Example: while (i=5) is an infinite loop because it is a non zero value and while (i==5) is true

only when i=5. 11. What is type casting?

Type casting is the process of converting the value of an expression to a particular data type. Example: int x,y;c = (float) x/y; where a and y are defined as integers. Then the result of x/y is

converted into float. 12. What is the difference between „a‟ and “a”?

„a‟ is a character constant and “a” is a string. 13. What is the difference between while loop and do…while loop?

In the while loop the condition is first executed. If the condition is true then it executes the body of the loop. When the condition condition is false it comes of the loop. In the do…while loop first the statement is executed and then the condition is checked. The do…while loop will execute at least one time even though the condition is false at the very first time. 14. What is a Modulo Operator? 4

Programming in C


„%‟ is modulo operator. It gives the remainder of an integer division Example: a=17, b=6. Then c=%b gives 5. 15. How many bytes are occupied by the int, char, float, long int and double?

int - 2 Bytes char - 1 Byte float - 4 Bytes long int - 4 Bytes double - 8 Bytes 16. 16. What are the types of I/O statements available in „C‟?

There are two types of I/O statements available in „C‟. Formatted I/O Statements Unformatted I/O Statements 17. What is the difference between ++a and a++?

++a means do the increment before the operation (pre increment) a++ means do the increment after the operation (post increment) Example:

a=5; x=a++; /* assign x=5*/ y=a; /*now y assigns y=6*/ x=++a; /*assigns x=7*/ 18. What is a String?

String is an array of characters. 19. What is a global variable?

The global variable is a variable that is declared outside of all the functions. The global variable is stored in memory, the default value is zero. Scope of this variable is available in all the functions. Life as long as the program‟s p rogram‟s execution doesn‟t come to an end. e nd. 20. 20. What are the Escape Sequences present in „C‟

\n - New Line \b - Backspace \t - Form feed 5

Programming in C


\‟ - Single quote \\ - Backspace \t - Tab \r - Carriage return \a - Alert \” - Double quotes 21. Construct an infinite loop using while?

while (1) {} Here 1 is a non zero, value so so the condition is always true. So it is an infinite loop. 22. Write the limitations of getchar( ) and sacnf( ) functions for reading strings (JAN 2009) getchar( )

To read a single character from stdin, then getchar() is the appropriate. scanf( )

scanf( ) allows to read more than just a single cha racter at a time. 23. What is the difference between scanf() and gets() function?

In scanf() when there is a blank was typed, the scanf() assumes that it is an end. gets() assumes the enter key as end. That is gets() gets a new line (\n) terminated string of characters from the keyboard and replaces the „\n‟ with „\ „\0‟. 24. What is meant by Control String in Input/Output Statements?

Control Statements contains the format code characters, specifies the t ype of data that the user accessed within the Input/Output statements. 25. What is the output of the programs given below?

main() {{ float a; float a; int x=6, y=4; int x=6, y=4; a=x\y; a=(float) x\y; printf(“Value of a=%f”, a); printf(“Value printf(“Value of a=%f”,a); }} Output

1. 1.500000 6

Programming in C


26. What is the output of the following program when, the name given with spaces?

main() { char name[50]; printf(“\n printf(“\n name\n”); name\n”); scanf(“%s, name); printf(“%s”,name); } Output: Lachi (It only accepts the data upto the spaces) 27. What is the difference between while(a) and while(!a)?

while(a) means while(a!=0) while(!a) means while(a==0) 28. 28. Why we don‟t use the symbol „&‟ symbol, while reading a String through scanf()?

The „&‟ is not used in scanf() while reading string, because the character variable itself specifies as a base address. Example: name, &name[0] both the declarations are same. 29. What is the output of the program?

main() increment() {{ increment(); static int i=1; increment(); printf(“%d\ printf(“%d\n”,i) increment(); i=i+1; }} Output: 123 30. 30. Why header files are included in „C‟ programming?

This section is used to include the function definitions used in the program. Each header file has „h‟ extension and include using u sing ‟# include‟ directive at the beginning of a program.

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Programming in C


All statements should be written in lower case letters. Upper case letters are only for symbolic constants. Blank spaces may be inserted between the words. This improves the readability of statements. It is a free-form language; we can write statements anywhere between„{„ and „}‟.a = b + c;d = b*c;

31. 31. What do you mean by variables in „C‟?

A variable is a data name used for storing a data value. Can be assigned different values at different times during program execution. Can be chosen by programmer in a meaningful way so as to reflect its function in the program. Some examples are: Sum percent_1class_total. 32. List the types of operators.

Arithmetic operators Relational operators Logical operators Increment and Decrement operators Assignment operators Bitwise operators Comma operator Conditional operator 33. Give the syntax for the „for‟ loop statement

for (Initialize counter; Test condition; Increment / Decrement) { statements; } 34. What is the use of sizeof( ) operator?

The sizeof ( ) operator gives the bytes occupied by a variable. No of bytes occupied varies from variable to variable depending upon its data types. Example:

int x,y; printf(“%d”,sizeof(x));

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Programming in C


Output: 2 35. Write a program to swap the values of two variables (without temporary variable).

#include #include void main( ) { int a =5; b = 10; clrscr( ); prinf(“Before swapping a = %d b = %d “, a , b); a = a + b; B = a – a – b; b; a = a – a – b; b; prinf(“After swapping a = %d b = %d”, a,b); getch( ); } Output: Before swapping a = 5 b = 10 After swapping a = 10 b = 5 36. 36. Write short notes about main ( ) function in ‟C‟ program. (MAY 2009)

i) Every C program must have main ( ) function. ii) All functions in C, has to end with „( )‟ parenthesis. iii) It is a starting point of all a ll „C‟ programs. iv) The program execution starts from the opening b race „{„ and ends with closing brace „}‟, within which executable part of the program exists. PART - B 1. Explain in detail about programming paradigms.

Machine code Procedural languages 

COBOL 9

Programming in C 

FORTRAN



ALGOL



PL/I



BASIC


Features of C Programming Language Advantages of C Disadvantages of C Object-oriented programming 2. Explain in detail about structure of C program.

Draw the diagram for structure of C program Documentation section Link section Definition section Global declaration section main () function section Subprogram section 3. Explain in detail about decision control statements or two way selection in C language with syntax.

Decision making statement is depending on the condition block need to be executed or not which is decided by condition 

if



if-else



switch

Write the syntax and example program for each ea ch control statements 4. Explain detail about looping statements.

Process of repeatedly executing a collection of statement 

while loops



do while loops



for loops

Write the syntax and example program for each looping statements 10

Programming in C


5. Discuss about preprocessor directives. o

#include

o

#define

o

#undef

o

#ifdef

o

#ifndef

o

#if

o

#else

o

#elif

o

#endif

o

#error

o

#pragma

6. Describe storage classes with examples. o

auto

o

extern

o

static

o

register

Write the example program for each classes 7. What is an operator? Explain the arithmetic, relational, logical and assignment operators in C language.

Write all operator symbols and explain with ex ample program. 8. Write a program to calculate the area of a circle. 9. Write a C program to convert an integer into the corresponding floating point number. 10. Write a program to find whether a number is even or odd. 11. Write a C program to calculate the sum of numbers from m to n. 12. Write a C program to calculate the average of first n numbers. 13. Write a C program to determine whether a given number is a prime or a composite number. 14. Write a C program to determine whether the entered character is a vowel or not. UNIT - II 11

Programming in C


ARRAYS AND STRINGS PART - A 1. What is an array?

An array is a group of similar data types stored u nder a common name. int a[10]; Here a[10] is an array with 10 values. va lues. 2. List the characteristics of Arrays.

All elements of an array share the same name, and they are distinguished form one another with help of an element number. Any particular element of an array can be modified separately without disturbing other elements. 3. What are the types of Arrays?

1.One-Dimensional Array 2. Two-Dimensional Array 3. Multi-Dimensional Array 4. What is the use of „\ „\0‟ character?

When declaring character arrays (strings), „\ „\0‟ (NULL) character is automatically added at end. The „\ „\0‟ character acts as an end of character array. 5. Define Strings.

The group of characters, digit and symbols enclosed within quotes is called as String (or) character Arrays. Strings are always terminated with „\ „ \0‟ (NULL) character. The compiler automatically adds „\ „\0‟ at the end of the strings. 6. Write an example for declaring ARRAYS.

Arrays may consist of any of the valid data types. Arrays are declared along with all other variables in the declaration section of the program. /* Introducing array's */ #include main() { int numbers[100]; float averages[20]; 12

Programming in C


numbers[2] = 10; --numbers[2]; printf("The 3rd element of array numbers is %d\n", numbers[2]); } 7. Write an example for assigning values to arrays.

The declaration is preceded by the word static. The initial values are enclosed in braces, Example

#include main() { int x; static int values[] = { 1,2,3,4,5,6,7,8,9 }; static char word[] = { 'H','e','l','l','o' }; for( x = 0; x < 9; ++x ) printf("Values [%d] is %d\n", x, values[x]); } 8. Define Multi-dimensional array.

Multi-dimensioned arrays have two or more index values which specify the element in the array. multi[i][j]; Declaration:

int m1[10][10]; static int m2[2][2] = { {0,1}, {2,3} }; 9. Example for character arrays [strings].

#include main() { static char name1[] = {'H','e','l','l','o'}; static char name2[] = "Hello"; printf("%s\n", name1); 13

Programming in C


printf("%s\n", name2); } 10. With syntax and example mention the method declaring an array. Syntax:

data_type array_name[array_size]={list_of_values};

Example:

int rollno[5]={4001,4002,4003,4004,4005}; rollno[5]={4001,4002,4003,4004,4005}; 11. Given an array int salary[5]={10000,8500,15000,7500,9000}. Calculate the address of salary[4] if the base address=1000.

Here, the size of the datatype int is 2. The value for w=2 Address of salary[4] =1000+2(4-0) =1000+8 =1008 12. Given an array int a[10]={101,012,103,104,105,106,107,108,109,110}. Show the memory representation and calculate its length. Memory Representation:

101

102

103

104

105

106

107

108

109

110

a[0] a[1] a[2] a[3] a[4] a[5] a[6] a[7] a[8] a[9] Length calculation:

Length of an array=upper_bound - lower_bound + 1 Here, upper_bound = 9 and lower_bound = 0 Thus, length of an array = 9-0+1 = 10 13. Write a C program to get 10 inputs for an array.

#include #include void main() { int i,number[5]; printf("Enter ten numbers:"); 14

Output: Enter ten numbers:23 45 67 89 10 20 30 40 50 The inputs of given array 23 45 67 89 10 20 30 40 50

Programming in C


for(i=0;i<10;i++) scanf("%d",&number[i]); printf("The inputs of given array\n"); for(i=0;i<10;i++) printf("%d",number[i]); } 14. Write a program to copy the value of an array to another.

#include #include void main() Output: The content of Array A: 1 2 3 4 5

{ int i,a[5],b[5]={1,2,3,4,5}; for(i=0;i<5;i++) a[i]=b[i]; printf("The content of array A:\n); for(i=0;i<5;i++) printf("%d",a[i]); } 15. List the applications of array.

The arrays are used in C programming p rogramming frequently because, 

Mathematical vectors and matrices can be easily implemented using arrays.



One dimensional array can be used as database where the elements are the records.



Strings, stacks, queue, heaps and hash tables can be implemented using arrays.



Sorting of elements into ascending order and descending order can be performed using arrays.

16. List the different methods for reading and writing a string.

The different methods for reading a string are, 

scanf()



gets()



getchar() 15

Programming in C




getch() or getche() The different methods for writing a string are,



printf()



puts()



putchar()

17. Write a C program to get a string input and print it.

#include #include void main() Output: Excellent The given string Excellent

{ char str[20]; gets(str); printf("The given string\n"); printf("%s",str); }

18. Why is it necessary to give the size of an array in an array declaration?

When an array is declared, the compiler allocates a base address and reserves enough space in the memory for all the elements of the array. The size is required to allocate the required space. Thus, the size must be mentioned. 19. What is the use of gets() function?

The gets() function allows a full line entry from the user. When the user presses the enter key to end the input, the entire line of characters is stored to a string variable. 20. Mention the various string manipulation function in C. S.No

Function

1

strcpy(s1,s2)

Copies string s2 into string s1.

2

strcat(s1,s2)

Concatenates string s2 onto the end of string s1.

3

strlen(s1)

Returns the length of string s1

4

strcmp(s1,s2)

5

strchr(s1,ch)

Purpose

Returns 0 if s1 and s2 are the same; less than 0 if s1s2. Returns a pointer to the first occurrence of character ch in string s1. 16

Programming in C

6

strst(s1,s2)


Returns a pointer to the first occurrence of sting s2 in string s1.

21. Write a C program to find the average of n (n < 10) numbers using arrays

#include int main() Output: Enter n: 6 Enter number 1:30 Enter number 2:40 Enter number 3:76 Enter number 4:80 Enter number 5:100 Enter number 6:142 Average= 78

{ int marks[10], i, n, sum = 0, average; avera ge; printf("Enter n: "); scanf("%d", &n); for(i=0; i
#include int main() { char s[1000], i;

Output: Enter a string: Programming in C Length of string:16

printf("Enter a string: string: "); scanf("%s", s); for(i = 0; s[i] != '\0'; ++i); printf("Length of string: %d", i); i); return 0; } 17

Programming in C


23. Write a C program to Read & write Strings in C using Printf() and Scanf() functions

#include #include int main() {

Output: Enter your Nick name: Negan Negan

char nickname[20]; printf("Enter your Nick name:"); scanf("%s", nickname); printf("%s",nickname); return 0; }

24. Write a C program to Read & Write Strings in C using gets() and puts() functions

#include #include int main() { char nickname[20]; puts("Enter your Nick name:"); gets(nickname);

Output: Enter your Nick name: Negan Negan

puts(nickname); return 0; } 25. How to compare two string using function?

#include #include int main() { Output: string 1 and 2 are different

char s1[20] = "BeginnersBook"; char s2[20] = "BeginnersBook.COM"; if (strcmp(s1, s2) ==0) 18

Programming in C


{ printf("string 1 and string 2 are equal"); }else { printf("string 1 and 2 are different"); } return 0; } PART-B 1. Write a C program to find the greatest element in an array. Get the input from the user and the number of elements in the array should be greater than 10. 2. Write a C program to merge and sort the elements of two different arrays. 3. Write a C program to find the number of vowels and consonants in a sentence. 4. Write a C program to perform linear search using array. 5. Write a C program to perform binary search using array. 6. Write a C program to perform matrix operations using array. 7. Write a C program to find the standard deviation using array. 8. Write a C program to count number of words in a sentence. 9. Write a C program to check whether a string is palindrome. 10. Explain the standard string functions with example to support each type.

Array of characters String functions: 

strlen()



strcmp()



strcat()



strcpy()

11. Define arrays. Explain the array types with an example program for each type.

Collection or group of elements 

one dimensional array



two dimensional array 19

Programming in C




multi dimensional array UNIT - III FUNCTIONS AND POINTERS PART - A

1. What is function?

To break a program into segments are commonly known as functions. Each of which can be written more or less independently of the others. Every function in the program is supposed to perform a well-defined task. 2. Why are functions needed? 

Dividing the program into separate well defined functions facilitates each function to be written and tested separately. This simplifies the process of getting the total program to work.



Understanding, coding and testing multiple separate functions is easier than doing the same for one big function.



If a big problem has to be developed without using any function fun ction other than main(), then there will be countless lines in the main() function and maintaining that program will be difficult task.

3. What is function prototype or function interface?

A function definition specifies how the function does what it does (implementation), a function prototype merely specifies its interface, (i.e) what data types go in and come out of it. The term function prototype is particularly used in forward declarations of functions in header files allows for splitting a program into translation units. 4. What is function declaration?

Before using a function, the compiler must know the number of parameters and the type t ype of parameters that the function expects to receive and the datatype of value that it will return to the calling program. Placing the function decla ration statement prior to its use enables the compiler to make a check on the arguments used while calling that function. 5. Write the function parts.

The functions have two parts are, 20

Programming in C



Function header



Function body


6. Write the syntax of function. Syntax:

Return_datatype function_name(datatype var1, datatype var2,...) { .......... Statements ......... return (variable); } 7. What is function call?

The function call statement statement invokes the function. When a function is invoked, the compiler jumps to the called function to execute ex ecute the statements that are a part of that function. Once the called function is executed, the program control passes back to the calling function. Syntax:

function_name(var1,var2,...); 8. What are the points are to be noted while calling a function? 

Function name and number of arguments, type of arguments in the function call must be same as that given in the function declaration and the function header of the function definition.



Names (not types) of variables in the function declaration, function call and header of function definition may vary.



Arguments may be passes in the form of expressions ex pressions to the called function. In such a case, arguments are first evaluated and converted to the type of formal parameter and then the body of the function gets executed.

10. Differentiate call by value and call by reference. 

Call by value : The values of the variables are passed by the calling function to the called

function. 

Call by reference : The addresses of the variables are passed by the calling function to 21

Programming in C


the called function. 11. Write the advantages of call by reference technique.

The advantages of call by reference technique are, 

Arguments are not copies into the new variables, it provides greater time and space efficiency.



Function can change the value of the argument and the change is reflected in the calling function.

12. Write the disadvantages of call by reference technique.

However, the drawback of using this technique is that if inadvertent changes are caused cause d to variables in the called function then these changes would be reflected in calling function as original values would have been overwritten. 13. What is recursion?

Recursion is the process of repeating items in a self similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function. 14. What is pointer?

Every variable in C has a name and a value associated with it. When a variable is declared, a specific block of memory within the computer is allocated to hold the value of that variable. The size of the allocated block depends on the datatype. A pointer is a variable that contains the address of another variable. 15. How to declaring pointer variables?

The general syntax of declaring pointer variables can be given as below. data_type *ptr_name; 16. Define Null pointers.

Null pointer which is a special pointer value and does not point to any value. This means that a null pointer does not point to any valid memory address. To declare a null pointer, you ma y use the predefined constant NULL which is defined in several standard header files including , and 17. Define generic pointers. 22

Programming in C


A generic pointer is a pointer variable that has void as its data type. t ype. The void pointer or generic pointer is a special type of pointer that can point to variables va riables of any data type. It is declared like a normal pointer variable but using the void keyword as the pointer's data type. Example: void *ptr; 18. Define pointer to pointer.

The pointers in turn point to data or even to other pointers. To declare decla re pointer to pointer, just add an asterisk * for each level of reference. 19. Write the drawbacks of pointers.

Pointers are very useful in C, they are not no t free from limitations. If used incorrectly, pointers can lead to bugs that are difficult to unearth. Example: If you use a pointer po inter to read a memory location but that pointer is pointing to an incorrect location, then you may end up reading a wrong value. An erroneous input always leads to an erroneous output. Thus however h owever efficient our program code may be, the t he output will always be disastrous. 20. Differentiate * and &.

*

Value at operator

& Address operator

Gives value stored at particular address Gives address of variable

21. What does the following declaration tells compiler?

int *ptr; 

'ptr' is declared as that 'ptr' will be used onl y for storing the address of the integer valued variables.



We can also say that 'ptr' points top integer value at the address contained in 'ptr' as integer.

22. How to passing an entire one-dimensional array to a function?

While passing arrays as arguments to the function, only the name of the array is passed (,i.e, starting address of memory area is passed as argument). Example: #include float average(float age[]); int main() 23

Programming in C


{ float avg, age[] = { 23.4, 55, 22.6, 3, 40.5, 18 }; avg = average(age); /* Only name of array is passed as argument. */ printf("Average age=%.2f", avg); return 0; } float average(float age[]) { int i; float avg, sum = 0.0; for (i = 0; i < 6; ++i) { sum += age[i]; } avg = (sum / 6); return avg; } 23. Differentiate between an array and pointer?

The difference between arrays and pointers are as follows. No.

1

Array

Pointer

Array allocates space automatically

Pointer is explicitly assigned to point to an allocated space.

2

It cannot be resized.

It can be resized using realloc().

3

It cannot be reassigned.

Pointers can be reassigned.

Size of (array name) gives the number of

Size of (pointer name) returns the number of

bytes occupied by the array.

bytes used to store the pointer variable.

4

24. Write a C program to swap two numbers.

#include int main()

Output: 24

Enter the value of x and y:32 18 Before swapping X=32 Y=18

Programming in C


{ int x,y,temp; printf("Enter the value of x and y:\n"); scanf("%d%d",&x,&y); PRIntf("Before swapping\nX=%d\nY=%d\n",x,y); temp=x; x=y; y=temp; printf("After swapping\nX=%d\nY=%d\n",x,y); swapping\nX=%d\nY=%d\n",x,y); return 0; } 25. Demonstrate use of reference operator in C program.

#include int main() { Output:

int var = 5; printf("Value: %d\n", var);

Value: 5

printf("Address: %u", &var); //Notice, the ampersand(&) before var.

Address: 2686778

return 0; } PART-B 1. Explain in detail about recursion with example.

Function is called within the same function Write factorial program 2. Explain in detail about pointers with example.

Address of a value Advantage of pointer Usage of pointer Address Of Operator Declaring a pointer 25

Programming in C


NULL Pointer 3. Write a C program to compute sine series. 4. Design a scientific calculator using built-in functions in C. 5. Explain detail about pointers and arrays.

A pointer variable takes different addresses as value whereas, in c ase of array it is fixed. Relation between Arrays and Pointers 6. Write a C program to access array elements using Pointers. 7. Write a program in C to find the number of 500, 100, 50, 20, 10, 5, 2, 1 rupee notes in a given amount. 8. Write a C program to sort a list in alphabetic order using pointers. UNIT - IV STRUCTURES PART - A 1. Define structure.

Structure is a user defined data type in C. C . structure helps to construct a complex compl ex data type in more meaningful way. It is somewhat similar to an arra y. The only difference is that array is used to store collection of similar data types while structure can store collection of any type of data. A structure is therefore a collection of variables under a single name. structure is used to represent a record. 2. Define self referential structure.

A self referential structure is one of the data structures which refer to the p ointer to another structure of the same type. That is, a self referential structure, in addition to other data, contains a pointer to a data da ta that is of the same type as that of the structure. A self referential structure is used to create data structures like linked lists, stacks, etc. 3. Define dynamic memory allocation.

C dynamic memory allocation refers to performing manual memory mana gement in the C programming language via a group functions in the C standard library, namely malloc, realloc, calloc and free. To access structure member using pointers, memory can be allocated dynamically using malloc() function defined under "stdlib.h" header file. 4. Define typedef. 26

Programming in C


The typedef keyword enables the programmer to create a new data type name by using an existing data type. By using typedef, no new data is created, rather an alternate name is given to a known data type. Syntax:

typedef existing_data_type new_data_type;

Where, typedef statement does not occupy any memory; it simply defines a new type. 5. Define nested structure.

A structure can be placed within another structure, structure, i.e., a structure may contain an other structure as its member. A structure that contains another structure as its member is called a nested structure. The easier and clearer wa y is to declare the structures separately and then group them in the higher level structure. When you do this, take care to check that nesting must be done from inside out (from lowest level to the most inclusive level), i.e., d eclare the innermost structure, then the next level structure, working towards the ou ter (most inclusive) structure. 6. What is malloc()? 

malloc() takes a single argument (the amount of memory to allocate in bytes).



malloc() does not initialize the memory allocated.

7. What is calloc()? 

calloc() needs two arguments (the number of variables to allocate in memory and the size in bytes of a single variable).



calloc() guarantees that all bytes of the allocated memory block have been initialized to 0.

8. What is linked list?

A linked list is a collection of data elements called nodes in which the linear representation is given by links from one node to the next node. 9. What are the basic operations on linked list?

The basic operations on linked list are, (i) Create

(ii) Delete

(iii) Search

(iv) Insert

(v) Display

10. Differentiate structure and union. No.

1

Description Keyword

Size 2

Structure Union The keyword struct is used to The keyword union is used to define define a structure a union. The compiler allocates the The compiler allocates the memory memory for each structure by considering the size of the largest member. Size of the structure is ≥ memory. So, size of union is equal to 27

Programming in C

Memory 3 Value altering 4 Accessing members Initialization of members

5 6


to the sum of the each member's the size of largest member. size. Each member within a structure Memory allocated is shared by is assigned unique storage area of individual members of union. location. Altering the value of a member Altering the value of any of the will not affect other members of member will alter other member the structure. values. Individual member can be Only one member can be accessed at accessed at a time. a time. Several members of a structure Only the first member of a union can can initialize at once. be initialized.

11. Difference between array and structure. No.

Arrays An array is a collection of data items of same data types. Arrays can only be declared. There is no keyword for arrays. An array name represents the address of the starting element. An array cannot have bit fields.

1 2 3 4

Structure A structure is a collection of data items of different data types. Structures can be declared and defined. The keyword for structures is struct. A structure name is known as tag. It is a shorthand notation of the declaration. A structure may contain bit fields.

12. Notes on deletion in single linked list.

There are 3 situations for deleting the elements in a list. 

Deletion at beginning of the list.



Deletion at the middle of the list.



Deletion at the end of the list.

13. How traversing is happen in a linked list?

Traversing a linked list means accessing the nodes of the list in order to perform some processing on them. Remember a linked list always contains a pointer variable start which stores stores the address of the first node of the list. End of the list is marked by storing NU LL or -1 in the NEXT field of the last node. For traversing the linked list, we also make use of another pointer variable ptr which points to the node that is currently being accessed. 14. Define searching for a value in a linked list. 28

Programming in C


Searching a linked list means to find a particular pa rticular element in the linked list. A linked list consists of nodes which are divided into two fields, the data field and next field. So searching means finding whether a given value v alue is present in the data field of the node or not. If it is present, the algorithm returns the address of the node that contains the value. 15. What are the functions supports for dynamic memory allocation?

The functions supports for dynamic memory allocation are, i. malloc ii. realloc iii. calloc iv. free 16. Write the routines to delete the first node .

When the element is at first

temp=head head=head->next if(head==NULL) printf(”Element printf(”Element is not found”); found”); else if(head->data==x) { temp=head; head=head->next; free(temp); } 17. How to traverse or display the linked list?

if(temp==NULL) printf("The list is empty"); empty"); 29

Programming in C


while(temp!=NULL) { cout<data; temp=temp->next; } 18. Write the routines to delete the middle node .

Deletion at middle

ptr=head; while(ptr->next!=NULL) { if(ptr->next->data= =2) { temp=ptr->next; ptr->next=temp->next; free(temp); } } 19. How to represent a linked list using structure?

typedef struct node { int data; //data field struct node*next; //link field 30

Programming in C


}ptr; 20. Write the routine for create a linked list. When the list is empty

When the list is not empty

if(head==NULL) //When nothing in the list head=temp; else { ptr=head; while(ptr->next!=NULL) ptr=ptr->next; ptr->next=temp; } 21. Write the routine for Inserting a node at first.

temp->next=head; head=temp; 22. Write the routine for Insert at middle. 31

Programming in C


ptr=head; while(ptr!=NULL) { if(ptr->data==y) { temp->next=ptr->next; ptr->next=temp; } ptr=ptr->next; 23. How to access the members of structure.

A structure member variable is generally accessed using a '.' (dot) operator. The syntax of accessing a structure or a member of a structure can be given as: struct_var.member_name; A dot operator is used to select a particular p articular member of the structure. 24. How to copy and compare structure.

We can assign a structure to another structure of th e same type. Example:

If we have two structure variables emp1 and emp2 of type struct employee given as, struct employee emp1={111,'aaron','pc',750000}; struct employee emp2; then to assign one structure variable to anoth er, we will write emp2=emp1; 25. Write short notes on inserting a new node in a linked list. 32

Programming in C


There are three situations for inserting element in a list. i.

Insertion at the front of list.

ii.

Insertion in the middle of the list.

iii.

Insertion at the end of the list. PART - B

1. Explain linked list and its operation

Store a collection of elements Node Declaring a Linked list Creating a Node Traversing the list Write the routines for deleting a node, inserting a no de 2. Explain dynamic memory allocation.

Enables the C programmer to allocate memory at runtime Four functions 1. malloc() 2. calloc() 3. realloc() 4. free() Difference between static memory allocation and dynamic memory allocation 3. Explain nested structure.

Another structure as a member Two ways to define: Separate structure, Embedded structure Accessing Nested Structure 4. Explain self referential structure.

To create data structures like linked lists, stacks, etc 5. How to define and use the structure?

Allows you to hold different type of elements Defining structure Declaring structure variable 33

Programming in C


Accessing members of structure 6. Write a C program to store information in structure and display it 7. Write a C program to add two complex numbers. UNIT - V FILE PROCESSING PART - A 1. What do meant by file?

A file is a collection of related records. A file can have fixed length records or variable length records. 2. How a file does is represented?

A file represents a sequence of bytes on the disk where a group of related data is stored. File is created for permanent storage of data. 3. What are the needs of files?

To execute the program with large amount of input data is time consuming to enter the entire data. But, if file is created, this information can be accesses using few commands. 4. What is file pointer?

A file pointer is a pointer to a structure, which co ntains information about the file, including its name, current position of the file, whether the file is being read or written and whether errors or end of the file have occurred. 5. List the file attributes.

(i) File name (ii) File position (iii) File structure (iv) Read only (v) Hidden (vi) Volume label (vii) Directory (viii) Archive 6. Differentiate text file and binary file. No.

1 2 3 4

Text file Stores data in the form of alphabets, digits and other special symbols by storing their ASCII values. Small error in a textual file can be recognized and eliminated when we see. It can be readable by the human. Text file is created by the programmer.

7. What are the basic operations of file? 34

Binary file Contains a sequences or a collection of bytes made of 0 and 1.

Small error in a binary file corrupts the file and it is not easy to detect. It cannot be readable by the human. Binary file is generated by the compiler.

Programming in C


The basic operations in files are, i.

Creation of a new file

ii.

Opening an existing file

iii.

Reading data from a file

iv.

Writing data in a file

v.

Closing a file.

8. Write the steps for processing a file.

i.

Declare a file pointer variable.

ii.

Open a file using fopen() function.

iii.

Process the file using suitable function.

9. Give the syntax to open the file.

*fp = FILE *fopen(const char *filename, const char *mode); Here, *fp is the FILE pointer (FILE *fp), which w ill hold the reference to the opened(or created) file.filename is the name of the file to be opened and mode specifies the purpose of opening the file. 10. What does the mode a+ represent?

The file can be opened for reading and appending and create the file if it does not exist. The reading will start from the beginning but writing can only be appended. 11. What is getc() and getw()?

getc() is used to read a character from a file that has been opened in read mode by fopen() function. Syntax: int getc(FILE*stream); getw() is used to read a integer from a file that has been opened in read mode.

Syntax:

int getc(FILE*stream);

12. What is feof()?

The feof() function returns true in case if end of file is reached. It detects end of file marker in a file. 35

Programming in C


Syntax: int feof(FILE*stream); 13. What is the function fseek() and ftell()? fseek():

It is used to move the reading control to different positions using fseek function. Syntax:

fseek( file pointer, displacement, pointer position); Where file pointer ---- It is the pointer which points to the file. displacement ---- It is positive or negative. This is the number of bytes which are skipped

backward (if negative) or forward( if positive) positive) from the current position. This is attached with L because this is a long integer. ftell(): It tells the byte location of current position of cursor in file pointer. Syntax:

ftell(fptr);

14. What are the benefits of file organization methods? 

Rapid access to one or more records.



Ease of inserting/updating/deleting one or more records without disrupting the speed of accessing records.



Efficient storage of records.



Using redundancy to ensure data integrity.

15. Is random access is the best access method? If yes justify your answer.

Yes, the data or file can be b e accessed from any location in the memory. There is no wastage of time to reach the exact ex act location of the file. 16. What are the types of file access methods?

The files can be accessed in two ways. They are, Sequential access file: The data are placed in the file in a sequence like beads on a string. Data

are processed in sequence, one after another. To reach particular item of a data, all the data that proceeds must read it first. 36

Programming in C


Random access file: The data are placed into the file by going directly to the location in the file

assigned to each data item. Data are processed in any order. Particular item of data can be reached by going directly to it, without looking at any other data. 17. Where does the sequential file access is suitable?

Sequential files are generally used to generate reports or to perform sequential reading of large amount of data which some programs need to do such as payroll processing of all the employees of an organization. 18. Differentiate random and sequential access methods. No. 1

Sequential Access Read and write operation is dome sequentially, starting from the beginning of the file. 2 Record length can be different. 19. What is the use of key in sequential access?

Random Access A random-access data file enables you read or write information anywhere in the file

Record length is same.

The key field uniquely identifies a record in a file. Thus, every record has a different value for the key filed. Records can be sorted in either ascending or descending order. 20. give the advantages of sequential access. 



Simple and easy to handle. No extra overheads involved.



Sequential files can be stored on magnetic disks a s well as magnetic tapes.



Well suited for batch oriented applications.

21. Give the disadvantages of sequential access. 

Records can be read only sequentially.



If i record has to be read, then all the i-1 records must be read.



Does not support any update operation.



A new file has to be created and the original file has to be replaced with the new file that

th

contains the desired changes. 

Cannot be used for interactive applications.

22. What do you meant by random access?

To read data in the middle of the file and same can be accessed directly. File organization provides random access by directly jumping to the record which has to be accessed. 23. Why does random access files is very much essential? 37

Programming in C




Real time applications require immediate response.



Example: Respond to customer query about a bill sequencing through records for account is time-intensive.



Airline reservation systems.



Banking systems.



Point-of sale systems.

24. How does the address of the record to be accesses is calculated in random access method?

The address of the record to be accesses is calculated in random access method by, th

Address of i record=base_address+(i-1)*record_length 25. Give the features of random access method. 

Provides an effective way to access individual rec ords.



The record number represents the location of the record relative to the beginning of the file.



Records in a relative file are of fixed length.



Relative files can be used for both random as well as sequential access.



Every location in the table either stores a record o r is marked as FREE.

26. How can you say random access is the best method. 

Ease of processing.



If the relative record number of the record that has to be accessed is known, then the record can be accesses instantaneously.



Random access of records makes access to relative files fast.



Allows deletion and updation in a same file.



Provides random as well as sequential access of records with low overhead.



New records can be easily added in the free locations based on the relative record number of the record to be inserted.



Well suited for interactive applications.

27. What is meant by command line arguments? How many arguments used in command line?

38

Programming in C


Command line argument is a parameter supplied to t o the program when it is involved. It is mostly used when it is essential to control the user program from outside, command line arguments are passes to main() function. It accepts arguments from command line or from other shell scripts by following commands: int main(int argc,char *argv[]) Where,

argc-Counts the number of arguments on the the command line. argv[] - Pointer array which holds pointer of type char which points to the arguments

passed to the program. PART - B 1. Explain the various operations can be carried out in the file with example.

1. Creating a new file 2. Opening an existing file 3. Closing a file 4. Reading from and writing information to a file Write the functions in file operations Difference between Append and Write Mode 2. List the types of files. Discuss the different functions will be performed on the file.

Sequential file Random file fseek() ftell() rewind() 3. Describe in detail about the command line argument.

Parameter supplied to the program when it is invoked Write the syntax and example program. 4. Write a C program to read name and marks of n number of students from user and store them in a file. 5. Write a C program to read character by character from the user and write them into a file using fputc() and read the same data from the file using fgetc() and display that on the screen. 39

Programming in C


6. Write a program to read integer data from the user and write it into the file using putw() and read the same integer data from the file using getw() and display it on the output screen.

40

CS8251 Programming in C-question Bank With Answer Keys

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