foo.c: In function 'main':
foo.c:7:23: error: 'a\U0000ff0bb' undeclared (first use in this function)
    7 |         printf("%d\n",a＋b);
      |                       ^~~~
foo.c:7:23: note: each undeclared identifier is reported only once for each function it appears in

[Hydro](https://hydro.ac)提供评测服务