func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long n;     scanf( %lld , &n);     long long sum[n + 5], ans[n + 5], a;     cout <<  ? 1 2  << endl;     cin >> sum[1];     cout <<  ? 2 3  << endl;     cin >> sum[2];     cout <<  ? 1 3  << endl;     cin >> sum[3];     ans[1] = (sum[1] + sum[3] - sum[2]) / 2;     ans[2] = sum[1] - ans[1];     ans[3] = sum[3] - ans[1];     for (int i = 4; i <= n; i++) {       cout <<  ?   << i - 1 <<     << i << endl;       cin >> sum[i];       ans[i] = sum[i] - ans[i - 1];     }     cout <<  ! ;     for (int i = 1; i <= n; i++) {       cout <<     << ans[i];     }     printf(  n );     return 0;   }   