c程序新手 想问问这个问题怎么写？

#include "stdio.h"

int _tmain(int argc, _TCHAR* argv[])
{
    char s[100];
    printf("Input grade:");
    scanf("%s", s);
    if (s[0] >= 'A' && s[0] <= 'Z') s[0] += 32; 
    int x = s[1] == '+' ? 1 : (s[1] == '-' ? -1 : (s[1] == '\0' ? 0 : 9999));
    if (s[1] != '\0' && s[2] != '\0') x += 9999;
    x += (s[0] - 'a') * 3;
    int score = 9999;
    if (x == -1) score = 85;
    if (x == 0) score = 90;
    if (x == 1) score = 100;
    if (x == 2) score = 70;
    if (x == 3) score = 75;
    if (x == 4) score = 80;
    if (x == 6) score = 60;
    if (x == 9) score = 50;
    if (score == 50) printf("<60\n");
    if (score > 100) printf("Input Error!\n");
    if (score >= 60 && score <= 100) printf("%d\n", score);
    return 0;
}

如果问题得到解决，麻烦点下我回答右边的采纳，谢谢。