如何在字符串中去掉多余的空格？

String str = "  hello   world  ";
String result = str.trim();
System.out.println(result);  // 输出：hello   world

import re

str = "  hello   world  "
result = re.sub(r'\s+', ' ', str)
print(result)  # 输出：hello world

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

std::string removeExtraSpaces(std::string str) {
    std::istringstream iss(str);
    std::vector<std::string> words;
    std::string word;
    while (iss >> word) {
        words.push_back(word);
    }
    std::ostringstream oss;
    for (const auto& w : words) {
        oss << w << " ";
    }
    return oss.str();
}

int main() {
    std::string str = "  hello   world  ";
    std::string result = removeExtraSpaces(str);
    std::cout << result << std::endl;  // 输出：hello world
    return 0;
}