用c++写一个函数，统计字符串中大写，小写和数字字母个数

#include <stdio.h>
#include <ctype.h>

void count(char *str, int *upper, int *lower, int *digit, int *alpha) {
    *upper = 0;
    *lower = 0;
    *digit = 0;
    *alpha = 0;

    while (*str) {
        if (isupper(*str))
            (*upper)++;
        else if (islower(*str))
            (*lower)++;
        else if (isdigit(*str))
            (*digit)++;
        if (isalpha(*str))
            (*alpha)++;
        str++;
    }
}

int main() {
    char str[] = "Hello World 123";
    int upper, lower, digit, alpha;
    count(str, &upper, &lower, &digit, &alpha);
    printf("Upper case: %d\n", upper);
    printf("Lower case: %d\n", lower);
    printf("Digit: %d\n", digit);
    printf("Alphabet: %d\n", alpha);
    return 0;
}