#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, n, i, t, r = 0;
  while (cin >> t) {
    for (i = 0; i < t; i++) {
      cin >> a >> b >> n;
      if (n % 3 == 1)
        cout << b << endl;
      else if (n % 3 == 0)
        cout << a << endl;
      else {
        r = a ^ b;
        cout << r << endl;
        r = 0;
      }
    }
  }
  return 0;
}
