C Program to find Factorial of a number

C Program to find Factorial of a number

For any positive number n, its factorial is given by:

Factorial = 1*2*3*4....n

If a number is negative, factorial doesn’t exist and factorial of 0 is 1

This program takes an integer from user, If user enters negative integer, this program will display error message and if user enters non-negative integer, this program will display the factorial of that number.

Source code to find factorial of a number:

#include<stdio.h>

#include<conio.h>

void main()

{

clrscr();

 int n, count,  int factorial=1;

 printf("Enter an integer: ");

 scanf("%d",&n);

 if ( n< 0)

printf("Error!!! Factorial of negative number doesn't exist.");

 else

 {

 for(count=1;count<=n;++count)                  /* for loop terminates if count>n */

   {

         factorial*=count;                                /* factorial=factorial*count */

   }

 printf("Factorial = %d",factorial);

 }

 getch();

}

Output 1:

Enter and Integer: -5

Error!!! Factorial of negative number doesn't exist.

OUTPUT2:

Enter and Integer: 10

Factorial= 3628800