Use of Recursion in VB.NET

Recursion is the process where a method can call itself. I simple term, it is the process of calling a function from within the same function. Recursion seems like to call itself.

For Example, when you put two mirror parallel position on that time recursion happen because each mirror create  infinite form of its image.



To show you how recursion method works. I have created factorial function because to get factorial of any integer factorial function must call itself. Factorial of 3 must be 6. See the below code:

Code:

Module Module1
    Sub Main()
         Dim f As New Fact()
         Console.WriteLine("Factorial of 3 is :" & f.factorial(3))
         Console.WriteLine("Factorial of 4 is :" & f.factorial(4))
         Console.WriteLine("Factorial of 5 is :" & f.factorial(5))
         Console.WriteLine("Factorial of 6 is :" & f.factorial(6))
         Console.WriteLine("Factorial of 7 is :" & f.factorial(7))
         Console.WriteLine("Factorial of 8 is :" & f.factorial(8))
         Console.WriteLine("Factorial of 9 is :" & f.factorial(9))
         Console.WriteLine("Factorial of 10 is :" & f.factorial(10))
         Console.WriteLine("Factorial of 11 is :" & f.factorial(11))
         Console.WriteLine("Factorial of 12 is :" & f.factorial(12))
         Console.WriteLine("Factorial of 13 is :" & f.factorial(13))
         Console.ReadLine()
     End Sub
     Class Fact
         Public Function factorial(n As Integer) As Long
             Dim result As Long
             If n = 1 Then
                 Return 1
             Else
                 result = factorial(n - 1) * n
                 Return result
             End If
         End Function
     End Class
End Module

Output:

Figure 1