1032번: 명령 프롬프트

#include<iostream>
#include<string>
using namespace std;
int main()
{
    bool a = 0;
    int n;
    string name[51];
    cin >> n;
    for (int i = 0; i < n; ++i)
        cin >> name[i];
    for (int i = 0; i < name[0].length(); ++i, a = 0)
    {
        for (int j = 0; j < n; ++j)
            if (name[0].at(i) != name[j].at(i))
            {
                a = 1;
                cout << "?";
                break;
            }
        if (!a)
            cout << name[0][i];
    }
}