mod using string (handling all negetive).cpp

#include<iostream>
using namespace std;

int main() {
  int n,cas=0,T;
  string str;
  cin>>T;
  while(T--) {
    cin>>str>>n;
    long long r=0;
    int i;
    if(str[0]=='-') i=1;
    else i=0;
    for(;str[i];++i) {
      r=r*10+(str[i]-'0');
      r=r%n;
    }
    printf("Case %d: remainder=%lld\n",++cas,r);
  }
  return 0;
}