C program to find factorial using recursion

C program to find  factorial using recursion:

2! = 1*2 =2

                3! = 1*2*3 =6

                4! = 1*2*3*4 = 24

                5! = 1*2*3*4*5 = 120

                6! = 1*2*3*4*5*6 = 720

                7! = 1*2*3*4*5*6*7 = 5040

                8! = 1*2*3*4*5*6*7*8 = 40320

 Below is the c program to find factorial using recursion.

#include <stdio.h>

int factorial(int n){

                int i, fact=1;

                                if( n==0 || n== 1)

                                                fact=1;

                                else

                                                fact = n * factorial( n-1);

               

                return fact;

}

void main(){

   int number, i, fact =1;

   printf("provide the number to find factorial. ");

   scanf("%d",&number);

  

   // check number is greater than zero or not.

   if( number>=0){

          //  calling the factorial function to find factorial.

       fact= factorial(number);

                   printf("factorial of given number is %d", fact);

   }

   else{

                printf("factorial not defined for negative values....");

                printf("please enter positive numbers ");

                }

}

Output:

provide the number to find factorial.

5

factorial of given number is 120

Output:

provide the number to find factorial.

   1

factorial of given number is 1

Output:

provide the number to find factorial.

0

factorial of given number is 1

Output:

provide the number to find factorial.

     -5

  factorial not defined for negative values....

  please enter positive numbers

5! =    5 * factorial ( 4 )

                  4 *  factorial ( 3 )

                                2 *  factorial ( 2 )

                                                2 *  factorial ( 1 )

                                                                1