foo.cc: In function 'int main()':
foo.cc:6:13: warning: 'a' is used uninitialized in this function [-Wuninitialized]
  cout << (a + b - c ) / 2 << endl;
           ~~^~~
foo.cc:6:13: warning: 'b' is used uninitialized in this function [-Wuninitialized]
foo.cc:6:17: warning: 'c' is used uninitialized in this function [-Wuninitialized]
  cout << (a + b - c ) / 2 << endl;
          ~~~~~~~^~~~~

正在同步测试数据，请稍后
自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。