请解释这段代码

Please Explain This Piece of Code

本文关键字：代码 段代码 解释      更新时间：2023-10-16

所以我一直试图在c++中分割字符串并将内容转储到向量中。我找到了问题的答案，所以我复制了解决方案，并开始玩它来理解它，但它仍然显得非常神秘。我有下面的代码片段，这是我制作和复制材料的混合。我已经评论了每一行我理解的目的。有人可以填写剩下的评论(基本上解释他们做什么)。我想完全了解这个问题是如何解决的。

ifstream inputfile; //declare file
inputfile.open("inputfile.txt"); //open file for input
string m; //declare string
getline(inputfile, m); //take first line from file and insert into string
std::stringstream ss(m);
std::istream_iterator<std::string> begin(ss);
std::istream_iterator<std::string> end;
std::vector<std::string> vstrings(begin, end);
std::copy(vstrings.begin(), vstrings.end(), std::ostream_iterator<std::string>(std::cout, "n"));
while(true) //delay the cmd applet from closing
{
}

免责声明:真正的代码不应该包含我将要使用的注释。(它也不应该如此固执的神秘。)

我已经添加了一个函数体和必要的头文件。

#include <iostream>
#include <string>
#include <sstream>
#include <fstream>
int main()
{
   // Construct a file stream object
   ifstream inputfile;
   // Open a file
   inputfile.open("inputfile.txt");
   // Construct a string object
   string m;
   // Read first line of file into the string
   getline(inputfile, m);

   // Copy the string into a stringstream so that we can
   // make use of iostreams' formatting abilities
   std::stringstream ss(m);
   // Construct an iterator pair. One is set to the start
   // of the stringstream; the other is "singular", i.e.
   // default-constructed, and isn't set anywhere. This
   // is sort of equivalent to the "null character" you
   // look for in C-style strings
   std::istream_iterator<std::string> begin(ss);
   std::istream_iterator<std::string> end;
   // Construct a vector by iterating through the text
   // in the stringstream; by default, this extracts space-
   // delimited tokens one at a time. The result is a vector
   // of single words
   std::vector<std::string> vstrings(begin, end);
   // Again using iterators (albeit un-named ones, obtained
   // with .begin() and .end()), stream the contents of the
   // vector to STDOUT. Equivalent to looping through `vstrings`
   // and doing `std::cout << *it << "n"` for each one
   std::copy(
      vstrings.begin(),
      vstrings.end(),
      std::ostream_iterator<std::string>(std::cout, "n")
   );
   // Blocks the application until it is forcibly terminated.
   // Used because Windows, by default, under some circumstances,
   // will close your terminal after the process ends, before you 
   // can read its output. However: THIS IS NOT YOUR PROGRAM'S
   // JOB! Configure your terminal instead.
   while (true) {}
}
可以这么说，

不是打印到控制台的最佳方式，以换行符分隔，在磁盘上的文本文件的第一行找到每个标记。请不要一字不差地从互联网上复制代码，并期望红海分开。

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