在C ++中，我将如何从一个文本文件获取一个特定的行并将其存储在一个char向量？ [英] In C++ how would I go about getting a specific line from a text file and storing that in a char vector?

问题描述

我想让我的程序打开一个文本文件，下到一个特定的行（例如，第18行），并将该行上的每个字符存储在一个char向量中。

I want to have my program open a text file, go down to a specific line (for example, line 18) and store each character on that line in a char vector.

我一般来说不熟悉编程，所以这可能不是最好的方法，但这里是我打算做的：

I'm fairly new to programming in general so this may not be the best way but here's what I plan on doing:

1）获取特定行和将其存储在字符串中

1) Get specific line and store it in a string

2）将该字符串转换为char向量。我使用一个向量而不是一个数组，所以我可以使用pushback（）使向量所需的精确大小，而不是在数组中分配太多或太少。

2) Convert that string to a char vector. I'm using a vector instead of an array so I can use pushback() to make the vector the exact size needed instead of allocating too much or too little in an array.

我可以做第2步很好，但它是第1步我有麻烦。我如何让它去一个特定的行？

I can do step 2 just fine but it is step 1 I'm having trouble with. How do I make it go to a specific line?

推荐答案

只读所有行，忽略您不感兴趣的行：

Just read all lines and ignore those you are not interested in:

#include <iostream>
#include <fstream>
#include <string>

int main()
{
        std::ifstream file("file.ext");
        std::string line;
        unsigned int line_number(1);
        const unsigned int requested_line_number(4);
        while (std::getline(file, line))
        {
                if (line_number == requested_line_number)
                {
                        std::cout << line << "\n";
                }
                line_number++;
        }
}

这段代码当然没有错误处理，自然，你不想在大多数时候硬编码你的行号，但是你的想法。

This code is of course devoid of error handling, and naturally, you wouldn't want to hardcode your line number most of the time, but you get the idea.

此外，我真的不知道什么char向量/ array是for。使用 std :: string 为您的字符串处理需求，这是它的作用。

Also, I don't really see what the char vector / array is for. Use std::string for your string handling needs, that's what it's made for.

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