text: #include <iostream>
  using namespace std;
  
  int main() {
  
      int x = 10, y = 3;
      // cin >> x >> y;
      // 把cin流重定向到文件test.txt
      freopen("test.txt", "w", stdout);
      if (y == 0) {
          cerr << "error." << endl;
      }
      else {
          cout << x << "/" << y << "=" << x/y << endl;
      }
  
      return 0;
  }