foo.cc: In function 'int main()':
foo.cc:12:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int x=1;x<=a;x++)
  ^~~
foo.cc:17:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   cout<<b<<endl;
   ^~~~
foo.cc:11:6: warning: unused variable 'cnt' [-Wunused-variable]
  int cnt=0; 
      ^~~