/in/foo.c: In function 'main':
/in/foo.c:28:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d", n1);
          ^
/in/foo.c:40:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d", n2);
          ^