如果输入空行或null，如何跳出while循环？

while True:
    user_input = input("请输入内容：")
    if not user_input:
        break

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            String userInput = scanner.nextLine();
            if (userInput.isEmpty()) {
                break;
            }
        }
    }
}

#include <iostream>
#include <string>

int main() {
    std::string userInput;
    while (true) {
        std::getline(std::cin, userInput);
        if (userInput.empty()) {
            break;
        }
    }
    return 0;
}