c语言实现 s_gets

#include 
#include 

#define ANSWER "Grant"
#define SIZE 40
char *s_gets(char *st, int n);

int main(void)
{
    char try_get[SIZE];

    puts("Who is buried in Grant's tomb?");
    s_gets(try_get, SIZE);
    while(strcmp(try_get, ANSWER) != 0)
    {
        puts("No, that's wrong, Try again.");
        s_gets(try_get, SIZE);
    }

    puts("That's right!");

    return 0;
}

char *s_gets(char *st, int n)
{
    char *ret_val;
    int i = 0;

    ret_val = fgets(st, n, stdin);
    if(ret_val)
    {
        while(st[i] != '\n' && st[i] != '\0')
        {
            i++;
        }
        if(st[i] == '\n')
        {
            st[i] = '\0';
        }
        else
        {
            while(getchar() != '\n')
            {
                continue;
            }
        }
    }

    return ret_val;
}