#include <stdio.h>
#define LEN 10
char * getnchar(char * str, int n);
int main(void)
{
    char input[LEN];//prepare the memory block when main() is executing.
    char *chk;

    chk = getnchar(input, LEN - 1);
    //this if branch has no sense in terms of usage except the first console input is EOF
    //I hasn't caught any implementation in the corresponding function
    if (chk == NULL)
        puts("Input failed.");
    else
        puts(input);
    puts("Done.\n");

    return 0;
}

char * getnchar(char * str, int n)
{
    int i;
    int ch;

    for (i = 0; i < n; i++)
    {
        ch = getchar();
        if (ch != EOF)
            str[i] = ch;
        else
            break;
    }
    //????????? logic has no sense to me.
    if (ch == EOF)
        return NULL;
    else
    {
        str[i] = '\0';
        return str;
    }
}