foo.c: In function 'main':
foo.c:8:16: warning: unused variable 'j' [-Wunused-variable]
    8 |         int i, j,num,max=0;
      |                ^
foo.c:30:36: warning: 'num' may be used uninitialized [-Wmaybe-uninitialized]
   30 |                                 num++;
      |                                 ~~~^~
foo.c:8:18: note: 'num' was declared here
    8 |         int i, j,num,max=0;
      |                  ^~~

[Hydro](https://hydro.ac)提供评测服务