/in/foo.c: In function 'main':
/in/foo.c:17:2: warning: implicit declaration of function 'system' [-Wimplicit-function-declaration]
  system("pause");
  ^~~~~~
/in/foo.c:6:6: warning: 'x' is used uninitialized in this function [-Wuninitialized]
  if(x>0&&y>0)
     ~^~
/in/foo.c:6:11: warning: 'y' is used uninitialized in this function [-Wuninitialized]
  if(x>0&&y>0)
          ~^~