Ques : Describe VBScript procedures

 In VBScript there are two kinds of procedures; the Sub procedure and the Function procedure.

Sub Procedures
A Sub procedure is a series of VBScript statements, enclosed by Sub and End Sub statements, that perform actions but don't return a value. A Sub procedure can take arguments (constants, variables, or expressions that are passed by a calling procedure). If a Sub procedure has no arguments, its Sub statement must include an empty set of parentheses ().
The following code shows a Sub procedure uses two intrinsic, or built-in, VBScript functions, MsgBox and InputBox, to prompt a user for some information. It then displays the results of a calculation based on that information. The calculation is performed in a Function procedure created using VBScript. The Function procedure is shown after the following discussion.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub

Function Procedures
A Function procedure is a series of VBScript statements enclosed by the Function and End Function statements. A Function procedure is similar to a Sub procedure, but can also return a value. A Function procedure can take arguments (constants, variables, or expressions that are passed to it by a calling procedure). If a Function procedure has no arguments, its Function statement must include an empty set of parentheses (). A Function returns a value by assigning a value to its name in one or more statements of the procedure. The return type of a Function is always a Variant.

In the following example, the Celsius function calculates degrees Celsius from degrees Fahrenheit. When the function is called from the ConvertTemp Sub procedure, a variable containing the argument value is passed to the function. The
result of the calculation is returned to the calling procedure and displayed in a message box.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub
Function Celsius(fDegrees)
Celsius = (Degrees - 32) * 5 / 9
End Function