为什么可以从函数返回向量？ [英] Why it is OK to return vector from function?

问题描述

请考虑这段代码，我已经看过这种类型的代码几次， words 是局部向量，如何从函数返回。我们能保证它不会死吗？

Please consider this code, I have seen this type of code several times, words is local vector, how it is possible to return from function. Can we guarantee it will not die?

 std::vector<std::string> read_file(const std::string& path)
 {
    std::ifstream file("E:\\names.txt");

    if (!file.is_open())
    {
        std::cerr << "Unable to open file" << "\n";
        std::exit(-1);
    }

    std::vector<string> words;//this vector will be returned 
    std::string token;

    while (std::getline(file, token, ','))
    {
        words.push_back(token);
    }

    return words;
}

推荐答案

我们可以保证它不会死吗？

Can we guarantee it will not die?

只要没有返回参考，这是完全正常的。 单词将被移动到接收结果的变量。

As long there is no reference returned, it's perfectly fine to do so. words will be moved to the variable receiving the result.

局部变量将超出范围。在移动（或复制）后。

The local variable will go out of scope. after it was moved (or copied).

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