杭电OJ 1002

#include <iostream>
#include <string>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define SWAP(a,b) auto c=a;a=b;b=c;

int main()
{
    int n = 0, c;
    string a, b, ans;
    cin >> n;
    FOR(i, 1, n+1){
        cin >> a >> b;
        cout << "Case " << i << ":" << endl;
        cout << a << " + " << b << " = "; // << a + b << endl << endl;

        if (a.size() < b.size()) {
            SWAP(a,b)
        }
        c = 0;
        ans = "";
        
        FOR(j, 0, b.size()){
            char a_num = a[a.size()-1 - j];
            char b_num = b[b.size()-1 - j];
            int res = a_num + b_num - 2 * ‘0‘ + c;
            c = res / 10;
            res %= 10;
            ans = char(res + ‘0‘) + ans;
        }
        FOR(j, b.size(), a.size()){
            char a_num = a[a.size()-1 - j];
            int res = a_num - ‘0‘ + c;
            c = res / 10;
            res %= 10;
            ans = char(res + ‘0‘) + ans;
        }
        cout << ans << endl;
        if(i != n) cout << endl;
    }
    return 0;
}