/in/foo.cc: In function 'int main()':
/in/foo.cc:7:14: warning: 'y' is used uninitialized in this function [-Wuninitialized]
  cout<<n-ceil(y/x);
          ~~~~^~~~~
/in/foo.cc:7:14: warning: 'x' is used uninitialized in this function [-Wuninitialized]
/in/foo.cc:7:18: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  cout<<n-ceil(y/x);
                  ^