foo.c: In function 'main':
foo.c:16:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
   16 |  scanf("%d",&n);
      |  ^~~~~
foo.c:16:2: warning: incompatible implicit declaration of built-in function 'scanf'
foo.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | 
foo.c:20:2: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   20 |  printf("%d\n",count);
      |  ^~~~~~
foo.c:20:2: warning: incompatible implicit declaration of built-in function 'printf'
foo.c:20:2: note: include '<stdio.h>' or provide a declaration of 'printf'

[Hydro](https://hydro.ac)提供评测服务