Project Euler, Problem #5, C

#include <stdio.h>

/* The problem: 2520 is the smallest number that can be divided by
each of the numbers from 1 to 10 without any remainder. What is the
smallest positive number that is evenly divisible by all of the
numbers from 1 to 20? */

/* Since non-prime numbers in the range of 11 through 20 are all
divisible by a number in the range of 2 through 10, only numbers in
the former range are checked for being factors. Thus, the product of
these numbers should the maximum checked value. */

int main()
{
     long int product = 1;
     int i;
     for(i = 11; i < 21; i++)
          product *= i;

/* As the biggest factor is 20 and the check starts with 20, the
step should also be 20. */

     long int checked = 20;
     int interrupted;
     while(checked <= product)
     {
          interrupted = 0;
          for(i = 20; i > 10; i--)
               if(checked % i != 0)
               {
                    interrupted = 1;
                    break;
               }
          if(interrupted != 1)
          {
               printf("%ld\n", checked);
               break;
          }
          checked += 20;
     }
     return(0);
}

/* 232792560 */