Subject: Informatics (065) Ms. Kanchan(KHMS) Visual Basic (XI+XII) Viva Questions Q1. What is interface? Ans. Interfac Interface e is the visual visual part throug through h which user user interac interact t with applica application tion. . Q2. What is control? Ans. The icons icons with with which which the the user inter interact acts s are called called contr control. ol. Q3. What What are are vario various us type types s of of cont contro rol l avai availab lable le in VB? VB? Ans. (A) Intrin Intrinsic sic contr control: ol: The The control control that that always always found found on on toolbox. toolbox. (B) Active X control: It is interactive objects that can reside on any form that support OCX (OLE control) controls. e.g. Some standard Active X controls are: ADO Data Control, Data List, Common Dialog etc. (C) Insertable Objects: In this, other objects can be added to the toolbox such as Microsoft Excel etc. Q4. Q4. What What do do you you unde unders rsta tand nd by by a mes messa sage ge and and eve event nt? ? Ans. Event: Event: - Refers Refers to to the occurren occurrence ce of an activi activity. ty. Message: - Is the information/request sent to the application. Q5. What are pro prop perti rties in VB? Ans. Properti Properties es are charact characteris eristics tics of an object object that that control control its appear appearance ance and and /or behavior. Q6. What What is the the rela relatio tionsh nship ip betwe between en prop propert erties ies, , method methods s and eve events nts? ? Ans. Properti Properties: es: is an objec object t attribu attributes, tes, Method Method: : as its action action and and event: event: as its its responses. Q7. Q7. What What is a cont contai aine ner r cont contro rol? l? Ans. It is a contr control ol that that can hold hold another another control control within within it.e. it.e.g.F g.Frame rame, , PictureBox, form etc. Q8. Q8. What What doe does s fol follo lowi wing ng stat statem emen ents ts do in VB? VB? Ans. Show: Show: - Display Display a form form that that is curren currently tly not not visible. visible. This This method method automatically loads the form, if it is not loaded in memory already. Load Load: : used used to load load a for form m in in mem memor ory y pro progr gram amma mati tica call lly. y. Unload: - Used to remove a form from memory and release the memory space it was occupy, in loaded state. Hide: - Used to make a visible form invisible. The hidden form continues to reside in memory. Q9. What What is is the the diff differe erence nce betwe between en SDI SDI and and MDI MDI int interf erface aces? s? Ans. MDI (Multip (Multiple le Document Documents s interfac interface) e) allows allows the user user to open multipl multiple e windows windows at the same time. e.g. MS-Word is MDI application. SDI (Single Documents interface) allows the opening of single windows at any point of time. e.g. In window Notepad, only one data document can be opened at a time. Q10. Timer Timer contro control l genera generate te just just one event event name name it? it? Ans. ns. Timer mer even vent . Q11. What is focus? focus? When do GotFoc GotFocus us and and LostFoc LostFocus us event event occur occur? ? Ans. Focus Focus is the abilit ability y to receive receive user user input input through through mouse mouse or or keyboard. keyboard. When When an object has the focus, it can receive input from a user. The GotFocus event occurs when an object receive focus. The LostFocus event occurs when an object loses focus. Page 1
Made By Ms. Kanchan Khurana
Subject: Informatics (065)
Ms. Kanchan(KHMS)
Q12. What is control array? Ans. It is a group of control created on the same form, having same name and type. The control in a control array is distinguished on the basis of a property called index. Q13. Name the three file system controls? Ans. (1) Drive List Box (2) Directory List Box (3) File List Box. Q14. Name the control that cannot receive Focus? Ans. Frame, Image, label, Shape and Timer control. Q15. What is Data Control? Ans. A Data Control is a control used to connect a VB application to a database. Q16. List some important properties of a Data Control? Ans. Databasename, Exclusive, RecordSource, ReadOnly. Q17. Name some invisible control? Ans. Timer control, Common Dialog control, Image List. Q18. What is bound control? Ans. Bound control is the control that can provide access to a specific column or columns in a data source through a data control or through remote data. The bound controls are CheckBox, images, Label, PictureBox, TextBox. Q19. Name three common properties of bound control? Ans. Datasource, DataField and Datachange Q20. How PictureBox and Image controls are differ? Ans. PictureBox can also act as a container for other controls that an image control cannot do. Q21. What is a ToolBar? Ans. A ToolBar is a container for buttons that generally correspond to frequently used commands in an application’s menu. Q22. What is a StatusBar? Ans. StatusBar is a frame that contains various panels to inform the user about the status of an application. Q23. What is a Status Bar Panel? Ans. It is a section of status bar that is used to display information about a particular attribute of the application. Q24. What is Separator Bar? Ans. A bar on a menu that divides menu items into logical group is called a Separator Bar. It is used fro clarity and for dividing logically related menu items into logical groups. Q25. What are dynamic menus? Ans. Dynamic menus are menus to which menu items can be added or removed at runtime. Q26. What is OLE? Ans. OLE stands for object linking and Embedding. OLE is a way to link different applications. The application whose object is placed in other application is called source document and the document where this object is placed is called the destination document. Q27. What is embedded object? Ans. Embedded object is an object in a destination document that is a copy of information, created in another application. Page 2
Made By Ms. Kanchan Khurana
Subject: Informatics (065)
Ms. Kanchan(KHMS)
Q28. What for is an OLE container control used? Ans. The OLE container control enables us to add insertable objects to the form in our VB application. Q29. What is the difference between linked and embedded object?
Ans. An embedded object is placed in the destination document in complete form and it become part of the destination document. A linked object, on the other hand is actually a way to establish link between source and destination document. In this, an object is not placed in destination document; rather a link is placed here. Q30. What is a Recordset? Ans30. Recordset is a temporary table (dummy table), created in main memory, by VB to hold the data generated by a data source (e.g. a data control). Q31. What do you understand by implicit and explicit declaration? Ans31. Implicit declaration means usage of variable without declaring it, i.e. VB implicit declares its type to be variant. Explicit declarations means all variable must be declared before using it. It can be enforced by typing Option Explicit at the top of the module can enforce it. Q32. What is Modal and Modeless Form? Ans32. Modal Form is one that takes total control of the application and does not let the user work with other application until it is closed. Modeless Form on the other hand allows the user to interact with the other application/switching to any other forms. Q33. What is ADO? Ans33. ADO expands to ActiveX Data Objects. It is an application program interface from Microsoft, which is used with windows applications to get access to relational as well as non-relational database. Q34. What is OLDB? Ans34. OLEDB is a set of interfaces that provides uniform access to data stored in diverse data stores; using OLEDB one can access all types of databases in the same manner. Q35. What is Data Provider? Ans35. A data provider is a control, a set of objects or a mechanism that provides data to applications by connecting to a data store. Q36. What os ODBC? Ans36. ODBC (Open Database Connectivity) is an application-programming interface that enables application to access data from a variety of existing data source. Q37. Name some data aware controls: -both intrinsic and ActiveX controls? Ans37. (A) Intrinsic:- TextBox, CheckBox, Label, ListBox etc. (B) ActiveX:-DataGrid, Datalist, MsflexGrid etc. Q38. Name some major object involved in ADODB processing? Ans38. (i) Connection object (ii)command object (iii)Recordset Q39. List any three methods of the connection objects? Ans39. Open, Execute, Close. Q40. List at least four properties of a connection object? Ans40. (i) Connection String. (ii) Provider (iii) Cursor Location (iv) Connection Timeout Page 3 Made By Ms. Kanchan Khurana
Subject: Informatics (065)
Ms. Kanchan(KHMS)
Q41. What is DSN? Ans41. DSN (Data source Name) is a logical name used by ODBC to store the information required to access a data store. A DSN once created can be used later also for accessing data from it connected data store. Q42. Which command type would you specify as the data source for the following requirements? Ans42.
i. Entire table data is required: -adcmdTable. ii. A store procedure is to be executed: -adCmdStoredProc. iii. SQL command is to be executed: -adCmdText. iv. Source of data is unknown: - adCmdUnknown. Q43. How would you obtain the no of records in a ecordset? Ans43. RecordCount property of Recordset. Q44. Using what method SQL query can be run on connection object? Ans44. Execute. Q45. Compare Selection construct with iteration construct in VB? Ans45. Selection Construct Iteration Construct 1. These construct are used for branching the control flow depending upon a certain conditions. 1.These constructs are used fo rrepeating a set of statements depending upon a certain conditions. 2. Selection construct available in VB are IF,IF---else, nested IF, Select Case etc. 2. Iteration construct available in VB are For---Next,Do—while,Loop Q46. Discuss various Loop-Types in VB with example? Ans46. VB supports two basic loop-types:(i) Entry-Controlled/Pre-Tested/Top-Tested Loop:These loops are first tested for execution before the loop body executes. e.g. Do While--Loop, For--- Next,While---Wend. (ii) Exit-Controlled/Post-Tested/Bottom-Tested Loop:are the ones which are tested for execution after the loop body executes. e.g. Do— Loop until, Do---Loop while. Q47. What is a procedure? Ans47. A procedure is a named unit of a group of program statements that perform a well-defined task. It can be invoked other parts of the program. In other words a procedure is a named code block that is created to do a well-defined task. Q48. How many types of procedure are available in VB? Ans48. There are several types of procedure are available in VB:(i) Sub-Procedure: - is a procedure that performs a task but does not return a value. (ii) Event-Procedure: - is a sub-procedure associated with a specific event of an object. It gets invoked when specific event occurs for its object. E.g. Cmd_ok click () (iii) Property-Procedure: - are the procedures used for reading/setting of an object’s property value. Page 4 Made By Ms. Kanchan Khurana
Subject: Informatics (065)
Ms. Kanchan(KHMS)
(iv) General-Procedure: - is a procedure written by a programmer to solve an application specific problem. It is invoked when a call statement is executed for it. Q49. What are actual and formal parameters? Ans49. Actual parameters are those, which appear in the statement invoking the procedure function where as formal parameters are those which appear in the definition of the procedure function. Q50. What do you mean by scope of a variable? Ans50. The scope or visibility of a variable is the portion of code from which that variable can be accessed. Q51. What do you mean by lifetime of a variable? Ans51. It is the time period during which that variable stays alive and
occupies memory. Q52. How many types of scopes are supported in VB? Ans52. (i) Local Scope: - Variable can only be used in procedure/function in which it is defined. (ii)Global Scope: - Variable can be used globally I.e. throughout the application. (iii)Module Scope: - Variable can be used in all procedure/function defined in the module which contains the definition for the variable. Q53. What are various advantages of using procedure in VB application? Ans53. (i) Reduction in size of source code. (ii) Reduction in size of compiled code. (iii) Program becomes more maintainable. (iv) Logic becomes more understandable. Q54. Differentiate between following: Ans54.(A) Private/Local Variables and Public/Global Variable Private/Local Variables Public/Global Variable (1) These variable are usable and available only from the code within their own procedure. (1) These variable are usable and available in all procedure within an application. (2) They lose their value as soon as the execution of their parent is over. They retain their value throughout an application. (B) Private/Local Procedure and Public/Global Procedure Private/Local Procedure Public/Global Procedure (1) These procedure are usable and available only from the code within their own module (1) These procedure are usable and available in all modules within an application. (C ) Local Variable and Stacic Variable Local Variable Static Variable (1) They lose their value as soon as execution of their parent is over (1) They retain their value even after their parent procedure is over (2) Their lifetime is function/procedure run. (2) Their lifetime is application run Page 5 Made By Ms. Kanchan Khurana Subject: Informatics (065)
Ms. Kanchan(KHMS)
Q55. Name two ways in which arguments can be passed to procedures? Ans55. (1) By value (ii) By Reference Q56. How is pass by value is different from pass by reference in terms of variable passed? Ans56. Pass by value Pass by reference (1) A copy of actual parameters is passed to the called procedure. (i) Reference to the actual parameters is passed to the calling procedure. (2) The original content of the passed variable (actual parameters) are not affected by the called procedure/function. (2) The original content of the passed variable (actual parameters) are affected by the changes made in the called procedure/function. Q57. What do you understand by parameters or arguments? Ans57. A parameters or an argument is the data passed from a calling program to the called program.
Q58. What do you understand by optional arguments? Ans58. An optional arguments is the one to which the calling program might or might not pass a value while invoking a function/procedure. Q59. How is event procedure different from general procedure? Ans59. Event procedure is invoked by the runtime, in response to a user action or some internal activity. General procedure on the other hand needs to be invoked explicitly by the programmer. Q60. What is a function? Ans60. A function is a named block of code, which apart from doing a welldefined task, return some calculated value to the calling program/procedure. Q61. How is function similar to and different from a procedure? Ans61. Both function and procedure are general procedure that perform a specific task, can take arguments, perform a series of statements and change the value of its arguments. A function however, can return a value to the calling procedure whereas a sub-procedure cannot return any value. Q62. What is module? Ans62. A module is a container of many declarations and code. Q63. What types of modules are available in VB? Ans63. There are three types of modules are available in VB (i) Form Module: a) All the form that are added to a VB application are example of from module. b) These module have two types of views(design and code view) c) These modules are saved with extension .frm. (ii) Standard Modules: a) Module that has no user interface and is used to group certain procedure or declaration are called standard module. b) These module store general purpose code of application i.e. that are not specific to one single form of the application. Page 6
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(iii) Class Modules: a) A module that is used to create a user-defined data-type that can have properties, vents, general procedure etc. associated with it. b) Class module is stored with extension .cls. Q64. What are library/Built in function? Ans64. Functions that are predefined and already available in VB are called library/built-in –function. Q65. What are various built-in-function in VB? Ans65. (I) String Function (II) Numeric Function (III) Date/Time function Q66. Explain various String-Function with example? Ans66. Functions Description 1. Lcase(“STUDENT”)=student Description:- (convert given string into lowercase letters) 2. Ucase(“student”)=STUDENT Description:- (convert given string into uppercase letters) 3. Len(“STUDENT”)=7 Description:-(Find length of given string) 4. Ltrim(“$$$student”)=student Description:- (Remove spaces from left side of given string) 5. rtrim(“student$$$$”)=student Description:-(Remove spaces from right side of given string) 6. Trim(“$$student$$$”)=student
Description:- (Remove spaces from both side of given string) 7. Left(“VIDU PRIYA SHARMA”,5)=VIDU Description:- (Extract 5 leftmost character from given string) 8. Right(“VIDU PRIYA SHARMA”,6)=SHARMA Description:- (Extract 6 rightmost character from given string) 9. Mid(“VIDU PRIYA SHARMA”,3,6)=DU PRI Description:- (Extract characters starting from 3 postion to 6th position character from given string) Mid statement is also replace extract characters with text you specify e.g. Sinput=”VIDU $ SHARMA” Mid(sinput,5,1)=’-“ Ans=VIDU-SHARMA. In this example $ replace with ‘-‘ character at 5th postion 10. Instr(4,”INFORMATICS”,’s’,1)=11 Description:- (Searched character s in given string starting searching from 4th character onwards by ignoring case) 11. Instr(2,”INFORMATICS”,’s’,0)=0 Description:- (Searched character s in given string starting searching from 2nd character onwards by considering case) If Last argument in INSTR( ) is mission that is 1 or 0 then it is zero by default. 12. String(5,”*”)=***** Description:- (Print given character given no of times) 13. String(4,”ABC”)=AAAA Description:- (Print first character given no of times from a string) 14. String(6,66)=BBBBBB Description:-(Print character B(because ASCII value of B is 66 given no of times) Page 7 Made By Ms. Kanchan Khurana 15. STR(1302)=”1302” Description:-(Convert a number into string) 16. StrReverse(ANITA SHARMA”)=ATINA AMRAHS Description:-(Reverse the given string) 17. CHR(65)=A CHR(97)=a Description:-(Return a string conating the charcter associated with specified character code) 18. ASC(“AMAR”)=65 ASC(“delhi”)=100 Description:-(Return a ASCII value of first character of a given string)
