C++输入循环问题：如何实现无输入或按换行时终止输入

Let's walk through why your current code isn't working, then implement a solution that meets your requirement of stopping when the user enters nothing (just presses Enter) or input ends.

What's Wrong With the Original Code? #

• cin >> name skips whitespace automatically: This operator ignores all whitespace characters (spaces, tabs, newlines) and only reads non-whitespace sequences. That means it will never capture a newline character into your name string—so your if(name == '\n') check is both a type mismatch (comparing a std::string to a char) and functionally useless.
• Empty input handling is broken: When the user presses Enter without typing anything, cin >> name fails to read a valid non-whitespace token, which sets the stream's fail state. This will end your loop, but it's not intentional handling of the "empty input" case you want.

The Corrected Solution #

To properly read input lines and stop on an empty line, use std::getline instead. This function reads entire lines (including spaces) and stops at the newline character (which it discards, so we can easily check for empty lines):

#include <iostream>
#include <string>

int main() {
    std::string input_line;
    
    // Continue reading lines until input ends or we get an empty line
    while (std::getline(std::cin, input_line)) {
        if (input_line.empty()) {
            // User pressed Enter without typing anything—exit the loop
            break;
        }
        // Output the entered content (add std::endl if you want a newline after each output)
        std::cout << input_line;
    }
    
    std::cout << "Exited";
    return 0;
}

How This Works #

• std::getline(std::cin, input_line): Reads every character from the input stream until it hits a newline, storing the result (without the newline) in input_line.
• input_line.empty() check: If the user presses Enter without typing any characters, input_line will be empty, triggering our break to exit the loop.
• Stream termination: The loop will also exit if the input stream is closed (e.g., user presses Ctrl+D on Unix/Linux/macOS, or Ctrl+Z on Windows), which handles the "no more input" case.

内容的提问来源于stack exchange，提问作者Badhusha