UVa - 10035 - Primary Arithmetic

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
    long long first, second;
    int mod, carry;
    vector <int> carry1, carry2;
    while(cin >> first >> second){
        if(first == 0 && second == 0)break;
        while(first > 0){
            mod = first % 10;
            carry1.push_back(mod);
            first -= mod;
            first /= 10;
        }
        while(second > 0){
            mod = second % 10;
            carry2.push_back(mod);
            second -= mod;
            second /= 10;
        }
        int l1, l2, mn, mx, ans = 0, in_hand = 0, push;
        l1 = carry1.size(), l2 =carry2.size();
        mn = min(l1, l2);
        mx = max(l1, l2);
        push = mx - mn;
        for(int i = 0; i < push; i++){
            if(l1 > l2)carry2.push_back(0);
            if(l1 < l2)carry1.push_back(0);
        }
        for(int i = 0; i < mx; i++){
            carry = carry1[i] + carry2[i] + in_hand;
            if(carry >= 10){
                ans++;in_hand = 1;
            }
            else in_hand = 0;
        }
        if(ans == 0)cout << "No carry operation." << endl;
        else if(ans == 1)cout << ans << " carry operation." << endl;
        else cout << ans << " carry operations." << endl;
        carry1.clear(), carry2.clear();
    }
    return 0;
}