foo.c: In function 'main':
foo.c:20:9: warning: 'd' may be used uninitialized [-Wmaybe-uninitialized]
   20 |   a0=(a0-d)*10+d/(c/10);
      |      ~~~^~~
foo.c:13:24: note: 'd' was declared here
   13 |   unsigned long long c,d;
      |                        ^
foo.c:20:20: warning: 'c' may be used uninitialized [-Wmaybe-uninitialized]
   20 |   a0=(a0-d)*10+d/(c/10);
      |                  ~~^~~~
foo.c:13:22: note: 'c' was declared here
   13 |   unsigned long long c,d;
      |                      ^

[Hydro](https://hydro.ac)提供评测服务