C++：如何使用堆栈检查字符串中是否存在相同数量的字母'a‘和'b’

#include <iostream>
#include <stack>
#include <string>

bool checkEqualCount(const std::string& str) {
    std::stack<char> charStack;

    for (char c : str) {
        if (c == 'a' || c == 'b') {
            if (charStack.empty()) {
                charStack.push(c);
            } else if (charStack.top() == c) {
                charStack.pop();
            } else {
                charStack.push(c);
            }
        }
    }

    return charStack.empty();
}

int main() {
    std::string str = "ababab";
    bool result = checkEqualCount(str);
    if (result) {
        std::cout << "The string has equal count of 'a' and 'b'." << std::endl;
    } else {
        std::cout << "The string does not have equal count of 'a' and 'b'." << std::endl;
    }

    return 0;
}