foo.c:1:19: warning: extra tokens at end of #include directive
    1 | #include <stdio.h>#define SIZE 50
      |                   ^
foo.c: In function 'main':
foo.c:4:17: error: 'SIZE' undeclared (first use in this function)
    4 | int i=0,int_num[SIZE]; //定义数组大小
      |                 ^~~~
foo.c:4:17: note: each undeclared identifier is reported only once for each function it appears in
foo.c:4:9: warning: unused variable 'int_num' [-Wunused-variable]
    4 | int i=0,int_num[SIZE]; //定义数组大小
      |         ^~~~~~~

[Hydro](https://hydro.ac)提供评测服务