foo.c: In function 'main':
foo.c:24:9: warning: 'sum' may be used uninitialized [-Wmaybe-uninitialized]
   24 |         printf("%d",sum);
      |         ^~~~~~~~~~~~~~~~
foo.c:18:13: note: 'sum' was declared here
   18 |         int sum;
      |             ^~~

[Hydro](https://hydro.ac)提供评测服务