Program : -
#include<stdio.h>
#include<conio.h>
int main()
{
int n, count;
unsigned long long 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 = %lu",factorial);
}
getch();
}
Output 1 : -
Enter an integer: -5
Error!!! Factorial of negative number doesn't exist.
Output 2 : -
Enter an integer: 10
Factorial = 3628800
