题解

注意小心边界值,字母还要考虑大写

int main()
{
    char a;
    int Letters = 0, Digits = 0, Others = 0;
    while ((a = getchar()) != '?')
    {
        if ((a >= '0') && (a <= '9'))
            Digits++;
        else if ((a >= 'a') && (a <= 'z'))
            Letters++;
        else if ((a >= 'A') && (a <= 'Z'))
            Letters++;
        else
            Others++;
    }
    printf("Letters=%d\n", Letters);
    printf("Digits=%d\n", Digits);
    printf("Others=%d\n", Others);
    return 0;
}