foo.cc: In function 'int main()':
foo.cc:14:2: error: 'cnt' was not declared in this scope
  cnt++; 
  ^~~
foo.cc:14:2: note: suggested alternative: 'int'
  cnt++; 
  ^~~
  int
foo.cc:16:8: error: 'cnt' was not declared in this scope
  cout<<cnt<<endl;
        ^~~
foo.cc:16:8: note: suggested alternative: 'int'
  cout<<cnt<<endl;
        ^~~
        int