foo.cc: In function 'int main()':
foo.cc:8:2: error: 'num' was not declared in this scope; did you mean 'enum'?
    8 |  num=0;
      |  ^~~
      |  enum
foo.cc:29:17: error: expected ';' before '}' token
   29 |     printf("\n")
      |                 ^
      |                 ;
   30 |   }
      |   ~              
foo.cc:6:8: warning: unused variable 'B' [-Wunused-variable]
    6 |  int A,B,n,m,a,b;
      |        ^

[Hydro](https://hydro.ac)提供评测服务