如何从C++中的字符串中获取各种字符的数量？

#include <iostream>
#include <map>

int main() {
    std::string str = "Hello, World!";
    std::map<char, int> charCount;

    for (char c : str) {
        if (charCount.find(c) != charCount.end()) {
            charCount[c]++;
        } else {
            charCount[c] = 1;
        }
    }

    for (auto it = charCount.begin(); it != charCount.end(); ++it) {
        std::cout << "Character: " << it->first << ", Count: " << it->second << std::endl;
    }

    return 0;
}