从fstream读取单个字符？ [英] Reading a single character from an fstream?

问题描述

我想从stdio移动到iostream，这是非常困难的。我有一个基本的加载文件和关闭它们，但我真的没有一个线索，甚至一个流甚至是，或它们如何工作。

I'm trying to move from stdio to iostream, which is proving very difficult. I've got the basics of loading a file and closing them, but I really don't have a clue as to what a stream even is yet, or how they work.

在stdio一切都比较容易和直截了当的比较。我需要做的是

In stdio everything's relatively easy and straight forward compared to this. What I need to be able to do is

1. 从文本文件中读取单个字符。


2. 
   

$ b $

重复此操作，直到我读取文件中的所有字符。 b

我到目前为止没有多少：

What I have so far is.. not much:

int main()
{
    std::ifstream("sometextfile.txt", std::ios::in);
    // this is SUPPOSED to be the while loop for reading.  I got here and realized I have 
    //no idea how to even read a file
    while()
    {
    }
return 0;
}

我需要知道的是如何获取单个字符以及该字符实际上是存储的（是一个字符串？一个int？一个char？我可以自己决定如何存储它吗？）

What I need to know is how to get a single character and how that character is actually stored(Is it a string? An int? A char? Can I decide for myself how to store it?)

一旦我知道我想我可以处理其余的部分。我将字符存储在一个合适的容器中，然后使用开关根据实际是什么字符做事情。它看起来像这样。

Once I know that I think I can handle the rest. I'll store the character in an appropriate container, then use a switch to do things based on what that character actually is. It'd look something like this.

int main()
{
    std::ifstream textFile("sometextfile.txt", std::ios::in);

    while(..able to read?)
    {
        char/int/string readItem;
        //this is where the fstream would get the character and I assume stick it into readItem?
        switch(readItem)
        {
        case 1:
            //dosomething
              break;
        case ' ':
            //dosomething etc etc
              break;
        case '\n':
        }
    }
return 0;
}

请注意，我需要能够检查空格和新行，希望它的可能。这也将是方便如果，而不是一个通用容器我可以存储数字在一个int和chars在一个字符。

Notice that I need to be able to check for white space and new lines, hopefully it's possible. It would also be handy if instead of one generic container I could store numbers in an int and chars in a char. I can work around it if not though.

感谢任何人能够向我解释流如何工作，以及他们可能做什么。

Thanks to anyone who can explain to me how streams work and what all is possible with them.

推荐答案

你也可以抽象出一个用 streambuf_iterator 想要使用任何算法：

You also can abstract away the whole idea of getting a single character with streambuf_iterators, if you want to use any algorithms:

#include <iterator>
#include <fstream>

int main(){
  typedef std::istreambuf_iterator<char> buf_iter;
  std::fstream file("name");
  for(buf_iter i(file), e; i != e; ++i){
    char c = *i;
  }
}

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