foo.c: In function 'main':
foo.c:9:9: warning: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    9 |         scanf_s("%d%d%d", &num1, &num2, &num3);
      |         ^~~~~~~
      |         scanf
foo.c:18:9: error: 'else' without a previous 'if'
   18 |         else()
      |         ^~~~
foo.c:18:14: error: expected expression before ')' token
   18 |         else()
      |              ^

[Hydro](https://hydro.ac)提供评测服务