在C++中查找字符串中的重复单词时出现输出错误

#include <iostream>
#include <sstream>
#include <unordered_map>
#include <vector>

void findDuplicateWords(const std::string& str) {
    std::stringstream ss(str);
    std::string word;
    std::unordered_map<std::string, int> wordCount;

    // 提取单词并统计出现次数
    while (ss >> word) {
        ++wordCount[word];
    }

    // 输出重复单词及其出现次数
    for (const auto& pair : wordCount) {
        if (pair.second > 1) {
            std::cout << "重复单词: " << pair.first << "，出现次数: " << pair.second << std::endl;
        }
    }
}

int main() {
    std::string str = "This is a test string. This is a test string with duplicate words.";

    findDuplicateWords(str);

    return 0;
}