foo.cc: In function 'int ishw(int)':
foo.cc:33:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.cc: In function 'int main()':
foo.cc:9:6: warning: 'cnt' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int cnt;
      ^~~