/in/foo.c: In function 'main':
/in/foo.c:5:15: warning: variable 'a' set but not used [-Wunused-but-set-variable]
    5 |         int n,a,c,r;
      |               ^
/in/foo.c:16:17: warning: 'c' may be used uninitialized [-Wmaybe-uninitialized]
   16 |         for(int i=c-1;i>=0;i--){
      |                 ^
/in/foo.c:5:17: note: 'c' was declared here
    5 |         int n,a,c,r;
      |                 ^
/in/foo.c:23:9: warning: 'r' may be used uninitialized [-Wmaybe-uninitialized]
   23 |         printf("%d\n",r);
      |         ^~~~~~~~~~~~~~~~
/in/foo.c:5:19: note: 'r' was declared here
    5 |         int n,a,c,r;
      |                   ^