Slip 29 - A) Write a C program to calculate factorial of a number using user defined function.

Solution:

#include <stdio.h>

int fact(int);

int main()

{    int n;

        printf("Enter an integer: ");

    scanf("%d",&n);

    // show error if the user enters a negative integer

                   printf("Factorial of %d = %llu", n, fact(n));

        return 0;

}

int fact(int n)

{

int i;

unsigned long long factorial = 1;

for(i=1; i<=n; ++i)

        {

            factorial *= i;              // factorial = factorial*i;

           return factorial;

        }

}