如何使用std :: copy从文件流直接读取到容器? [英] How can I use std::copy to read directly from a file stream to a container?

问题描述

我遇到了一个很酷的STL示例，该示例使用istream_iterators从std输入(cin)复制到向量.

I ran across a cool STL example that uses istream_iterators to copy from std input (cin) to a vector.

vector<string> col1;
copy(istream_iterator<string>(cin), istream_iterator<string>(),
    back_inserter(col));

我将如何做类似的操作，将文件流直接读取到容器中?我们只说它是一个包含内容的简单文件:

How would I do something similar to read from a file-stream directly into a container? Let's just say its a simple file with contents:

敏捷的棕色狐狸跳过了懒狗."

"The quick brown fox jumped over the lazy dogs."

我希望每个单词在复制行之后成为向量中的单独元素.

I want each word to be a separate element in the vector after the copy line.

推荐答案

成功打开文件后，用文件流对象替换 cin :

Replace cin with file stream object after opening the file successfully:

ifstream file("file.txt");

copy(istream_iterator<string>(file), istream_iterator<string>(),
                                                 back_inserter(col));

实际上，您可以用任何C ++标准的 input 流替换 cin .

In fact, you can replace cin with any C++ standard input stream.

std::stringstream ss("The quick brown fox jumped over the lazy dogs.");

copy(istream_iterator<string>(ss), istream_iterator<string>(),
                                                 back_inserter(col));

有主意吗? col 将包含您传递给 std :: stringstream 的字符串的单词.

Got the idea? col will contain words of the string which you passed to std::stringstream.

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