Program to identify the Prime Number and Factorial with the use of recursion.

In many Interview, your interviewer can ask you to write the program for prime number and when you will listen this question than a cute smile will come at your face because internally you are feeling that this is very easy question.

And you are right, definitely its a simple program, but run time it can be happen that might be you will not able to recall the logic behind it.

Prime Number A Prime number can be divided evenly only by 1 or itself. And it must be a whole number greater 1.

a = Inputbox("Enter the Number")
Flag =0
   For i=2 to a-1
       If (a mod i =0) Then
            Flag =1
   Exit for
   End If
 Next

 If  (Flag=1) Then
         Msgbox a& " - Input Number is not Prime Number"
    elseif (a="0" or a="") then
    Msgbox "Invalid Input"
 else
    Msgbox  a&" - Input Number is a Prime Number"
 End If

When you Run this Program it will ask for your input, please input the Number

Now My Program will divide this number by all the numbers lower than 13 and check whether this number is prime or not

Factorial With use of Recursion:

Preview:

c=Inputbox( "Enter the Number for Factorial")
f = Fact (c)
msgbox  "Factorail of number  "&c&" "&"is"&" "&":"&" "&f

Function Fact (n)
If (n = 0) Then
            Fact = 1
        Else
            Fact = n * Fact(n - 1)
   
        End If
End Function

When you Run this Program it will ask for your input, Enter the Number for Factorial

Output would be: