Functions are named blocks of code that perform a specific task and return a result. They can take arguments and have a return data type. Procedures perform tasks but do not return results. There are two types of procedures: general procedures for specific purposes and event procedures associated with object events. Functions and procedures are called with or without the CALL keyword and can pass arguments by reference or by value.
Functions
It is aseparate procedure that can take arguments, perform a series of
statements and change the value of its argument
or
Functions are named blocks program code that perform a specific task
and return a result. The task can be as simple as adding two numbers
or as complex as launching a spacecraft
Syntax:
Function FunctionName(argument list) As Datatype
VB statements. . . .
End Function
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The arguments tothe function are declared as :
1. By ref
When passing by reference, the address of arguments are passed.
Example:
Public Function Sum(ByRef Number1 As Double, ByRef Number2 As
Double) As Double
Sum = Number1 + Number2
End Function
2. By val
When passing by value, copies of the arguments are passed.
Example:
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Procedures
Procedure is ablock of statements which performs a particular task,
just that it does not return a result
Syntax:
[Private|Public] Sub ProcedureName(argument list)
VB Statements. . . .
End Sub
Types of procedures:
1. General Procedure
General procedure is one that we create for our own specific
purpose.
2. Event Procedure
Event procedure is a procedure associated with the event of an
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object and are named in a way that indicates both event and object
clearly.
5.
Calling a Procedure
Procedureare called with or without the keyword call
Syntax:
….
Call procedurename()
….
Example:
Private Sub clearcontrols()
Text1.text = “ “
General Procedure
Text2.text = “ “
End Sub
Private Sub cmdreset_click()
Call clearcontrols() Event Procedure
End Sub 4