foo.cc: In function 'int main()':
foo.cc:18:12: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<x1<<" "<<x2;
            ^~~
foo.cc:18:15: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<x1<<" "<<x2;
  ~~~~~~~~~~~~~^~~~
foo.cc: In function 'int FindMaxNeg(int*, int)':
foo.cc:37:9: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return max;
         ^~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。