Sub Procedure in VB.net with Example

What is Sub Procedure in VB.net?

A Sub Procedures in VB.net is a separate set of codes that are used in VB.NET programming to execute a specific task, and it does not return any values. The Sub procedure is enclosed by the Sub and End Sub statement.

The VB.net Sub Procedures is similar to the function procedure for executing a specific task except that it does not return any value, while the function procedure returns a value.

In order for you to test your VB.net Code provided in this lesson, you must test the code in your code editor. But if you wish to run this code online, we also have an Online Compiler in VB.net for you to test your VB.net Code for free.

Difference Between Sub Procedure and Function in VB.net

Difference Between Functions and Su...
Difference Between Functions and Sub Routine in VB.Net 2019 Best Practices

A sub procedure is a group of VB.net statements. It begins with a Sub keyword and ends with End Sub keywords. A sub procedure is also called a subroutine.

It is used to execute a certain block of statements consists the body of the procedure. It is called explicitly by its name whenever it is required to perform a certain task. It can be called any number of times. The sub procedure returns control to the calling code after performing a task.

A function procedure is a group of VB.net statements. It begins with a Function keyword and ends with an End Function keyword.

It is generally used to perform a task and return a value back to the calling code. It may have multiple return points to the calling code. A part from return stamens, End Function, or Exit function also returns control to the calling procedure.

See also the Complete Topic About the Difference Between Sub Procedure and Function in VB.net.

Defining Sub Procedures in VB.net

A sub procedure’s name, parameters, and body are declared using the Sub statement.

Syntax for the Sub Procedure in VB.net:

'syntax for sub procedure'

[Modifiers] Sub SubName [(ParameterList)]
[Statements]
End Sub

1. Modifiers

Set the procedure’s access level; options include Public, Private, Protected, Friend, and Protected Friend. Include details on overloading, overriding, sharing, and shadowing.

2. SubName

Indicates the name of the Sub.

3. ParameterList

specifies the list of the parameters.

Example Program of Sub Procedure in VB.net:

Example: Write a simple program to pass the empty, a single or double parameter of Sub procedure in the VB.NET.

Module Sub_Program  
    Sub sample()  
        Console.WriteLine("Welcome to IT SOURCECODE")  
    End Sub  
  
    Sub circle(ByVal r As Integer)  
        Dim Area As Integer  
        Const PI = 3.14  
        Area = PI * r * r  
        Console.WriteLine(" Area Of circle is : {0}", Area)  
    End Sub  
  
    ' Create the SumOfTwo() Function and pass the parameters.  
    Sub SumOfTwo(ByVal n1 As Integer, ByVal n2 As Integer)  
        ' Define the local variable.  
        Dim sum As Integer = 0  
        sum = n1 + n2  
        Console.WriteLine(" Sum of two number is : {0}", sum)  
    End Sub  
  
    Sub SubtractionOfTwo(ByVal n1 As Integer, ByVal n2 As Integer)  
        ' Define the local variable.  
        Dim subtract As Integer  
        subtract = n1 - n2  
        Console.WriteLine(" Subtraction of two number is : {0}", subtract)  
    End Sub  
  
    Sub MultiplicationOfTwo(ByVal n1 As Integer, ByVal n2 As Integer)  
        ' Define the local variable.  
        Dim multiply As Integer  
        multiply = n1 * n2  
        Console.WriteLine(" Multiplication of two number is : {0}", multiply)  
    End Sub  
  
    Sub Main()  
        ' Define the local variable a, b and rad.  
        Dim a, b, rad As Integer  
        sample() ' call sample() procedure  
        Console.WriteLine(" Please enter the First Number : ")  
        a = Console.ReadLine()  
        Console.WriteLine(" Second Number is : ")  
        b = Console.ReadLine()  
  
        SumOfTwo(a, b) 'call SumOfTwo() Function  
        SubtractionOfTwo(a, b) 'call SubtractionOfTwo() Function  
        MultiplicationOfTwo(a, b) 'call MultiplicationOfTwo() Function  
  
        Console.WriteLine(" Enter the radius of circle : ")  
        rad = Console.ReadLine()  
        circle(rad)  
        Console.WriteLine(" Press any key to exit...")  
        Console.ReadKey()  
    End Sub  
End Module  

When the above code is compiled and executed, it produces the following result:

Welcome to IT SOURCECODE
Please enter the First Number :
5
Second Number is :
5
Sum of two number is : 10
Subtraction of two number is : 0
Multiplication of two number is : 25
Enter the radius of circle :
20
Area Of circle is : 1256
Press any key to exit…

Test your Code Here!

In the  VB.net programming language, we can pass parameters in two different ways:

  • Passing parameter by Value
  • Passing parameter by Reference

Passing Parameters by Value in VB.net

The default approach for sending a value in the Sub method in VB.NET is to pass a parameter by value. The method merely creates a new storage place for each parameter when it is called, copying the actual value of each argument into the formal method of the Sub process.

Consequently, the modifications made to the actual parameter of the main function do not change the formal argument of the Sub process.

Syntax for Passing Parameters by Value in VB.net:

'syntax for passing parameters by value'

Sub Sub_method( ByVal parameter_name As datatype )  
[ Statement to be executed]  
End Sub  

In the above syntax, the ByVal is used to declare parameters in a Sub procedure.

Example Program of Passing Parameter by Value in VB.net:

Module paramByval
   Sub swap(ByVal x As Integer, ByVal y As Integer)
      Dim temp As Integer
      temp = x ' save the value of x 
      x = y    ' put y into x 
      y = temp 'put temp into y 
   End Sub
   Sub Main()
      ' local variable definition 
      Dim a As Integer = 100
      Dim b As Integer = 200
      Console.WriteLine("Before swap, value of a : {0}", a)
      Console.WriteLine("Before swap, value of b : {0}", b)
      ' calling a function to swap the values '
      swap(a, b)
      Console.WriteLine("After swap, value of a : {0}", a)
      Console.WriteLine("After swap, value of b : {0}", b)
      Console.ReadLine()
   End Sub
End Module

When the above code is compiled and executed, it produces the following result:

Before swap, value of a : 100
Before swap, value of b : 200
After swap, value of a : 100
After swap, value of b : 200

Test your Code Here!

Passing Parameters by Reference in VB.net

A VB.net Reference Parameter is a memory location’s reference to a variable. When using ByRef in the Sub procedure, the Reference Parameter in VB.net is utilized to pass a variable’s reference.

A new storage location for the formal argument of the sub method is not created when a reference parameter is given. Furthermore, the actual parameters supplied to the method’s reference parameters represent the same memory address.

As a result, whenever we alter the formal parameter’s value, the memory immediately updates to reflect the new value.

Example Program for Passing Parameters by Reference in VB.net:

Module paramByref
   Sub swap(ByRef x As Integer, ByRef y As Integer)
      Dim temp As Integer
      temp = x ' save the value of x 
      x = y    ' put y into x 
      y = temp 'put temp into y 
   End Sub
   Sub Main()
      ' local variable definition 
      Dim a As Integer = 100
      Dim b As Integer = 200
      Console.WriteLine("Before swap, value of a : {0}", a)
      Console.WriteLine("Before swap, value of b : {0}", b)
      ' calling a function to swap the values '
      swap(a, b)
      Console.WriteLine("After swap, value of a : {0}", a)
      Console.WriteLine("After swap, value of b : {0}", b)
      Console.ReadLine()
   End Sub
End Module

When the above code is compiled and executed, it produces the following result:

Before swap, value of a : 100
Before swap, value of b : 200
After swap, value of a : 200
After swap, value of b : 100

Test your Code Here!

Summary

In this tutorial Sub Procedure in VB.net, we discuss about its uses and importance in a program, this tutorial also includes a Example Program to be executed. this tutorial is good for the beginners who wants to learn programming, especially VB.net Programming Language.


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