foo.cc: In function ‘int main()’:
foo.cc:10:20: error: invalid types ‘int[int]’ for array subscript
   10 |         int max=sum[1],u;
      |                    ^
foo.cc:20:35: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   20 |                 else if(qimo>85&&a=='Y')
      |                                  ~^~~~~
foo.cc:22:37: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   22 |                 else if(pingyi>80&&b=='Y')
      |                                    ~^~~~~