poj 2710 Consecutive Digits

#include<iostream>#include<stdio.h>using namespace std;int main(){    int cases, x = 1;    cin>>cases;    while (cases--) {        int a, b, c, d;        cin>>a>>b>>c>>d;        printf("Problem set %d: %d / %d, base 7 digits %d through %d: ", x++, a, b, c, d);        int i;        a %= b;        for (i = 0; i <= d; ++i) { a *= 7; if (i >= c) {     printf("%d", a / b); } a %= b;        }        printf("n");    }    return 0;}