A procedure is a collection of statements that, when called, complete a task. After the procedure is completed, control returns to the statement that is called the procedure. There are two kinds of procedures in VB.Net −

• Functions- return a value
• Sub procedures or Subs- do not return a value

Defining a Function

The Function statement is used to declare a function's name, parameters, and body. The Function statement has the following syntax−

[Modifiers] Function FunctionName [(ParameterList)] As ReturnType

[Statements]

End Function

Where,

• Modifiers − specify the function’s access level; possible values are Public, Private, Friend, Protected, Protected Friend and information regarding overloading, sharing, overriding, and shadowing.
• FunctionName − indicates the name of the function
• ParameterList – used to specify a list of the parameters
• ReturnType – used to specify the data type of the variable that the function returns

Function Return a Value

A function in VB.Net can return a value to the caller code in two ways: 

• by using the return statement 
• by assigning the value to the function name

Recursive Function

A recursive function can call itself. This is called recursion. 

Param Arrays

When declaring a function or subroutine, you may be unsure of the number of arguments supplied as parameters. At this point, VB.Net param arrays (or parameter arrays) come in handy.

An array can be passed as a function argument in VB.Net.