PEL-Protocol Engineering Lab.

#include <stdio.h>
 
int main(void) {
    const int m = 1000;
    int input;
    int res;
 
    do {
    printf("your input needed: ");
//    scanf("%d", &input);
    input = 10;
 
    res = m % input;
 
    } while(res != 0);
 
    printf("well done\n");
 
    return(0);
}