/in/foo.cc: In function 'int is(int, int*)':
/in/foo.cc:16:9: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return y;
         ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:25:17: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<is(x,a)<<" "<<is(y,b);
                 ^~~
/in/foo.cc:25:29: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<is(x,a)<<" "<<is(y,b);
                             ^