/in/foo.cc: In function 'int main()':
/in/foo.cc:15:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k;
          ^
/in/foo.cc:30:19: warning: 'e' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<b<<" "<<e<<" "<<ans<<endl;
                   ^~~
/in/foo.cc:30:11: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<b<<" "<<e<<" "<<ans<<endl;
           ^~~