#include <stdio.h>
long facto(long x);
int main()
{
    long n, a;
    printf("———————————————————————————————————————————");
    printf("\nProgram to find the factorial of a given number");
    printf("\n———————————————————————————————————————————");
    printf("\nEnter the number ");
    scanf("%ld", &n);
    if (n < 0)
    {
        printf("Please enter a positive number or zero");
    }
    else if (n >= 26)
    {
        printf("Please enter a number less than 26");
    }
    else
    {
        a = facto(n);
        printf("\nThe factorial of %ld is %ld", n, a);
    }
    printf("\n———————————————————————————————————————————\n");
    return 0;
}
long facto(long n)
{
    if (n >= 1)
    {
        return n * facto(n - 1);
    }
    else
    {
        return 1;
    }
}

kodingwindow@kw:~$ gcc kw.c
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to find the factorial of a given number
———————————————————————————————————————————
Enter the number 0

The factorial of 0 is 1
———————————————————————————————————————————

kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to find the factorial of a given number
———————————————————————————————————————————
Enter the number 25

The factorial of 25 is 7034535277573963776
———————————————————————————————————————————
kodingwindow@kw:~$