从文件中读取整数-逐行读取 [英] Read integers from file - line by line

问题描述

在C ++中，如何从文件读取整数到整数数组？因此，例如，该文件的内容：

How can I read integers from a file to the array of integers in c++? So that, for example, this file's content:

23
31
41
23

将变为：

int *arr = {23, 31, 41, 23};

？

我实际上有两个问题有了这个。首先是我真的不知道如何逐行阅读它们。对于一个整数，这将非常容易，只需 file_handler>>数字语法就可以了。

I actually have two problems with this. First is that I don't really know how can I read them line by line. For one integer it would be pretty easy, just file_handler >> number syntax would do the thing. How can I do this line by line?

对我来说，似乎更难克服的第二个问题是-我应该如何为这件事分配内存？ ：U

The second problem which seems more difficult to overcome for me is - how should I allocate the memory for this thing? :U

推荐答案

std::ifstream file_handler(file_name);

// use a std::vector to store your items.  It handles memory allocation automatically.
std::vector<int> arr;
int number;

while (file_handler>>number) {
  arr.push_back(number);

  // ignore anything else on the line
  file_handler.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
}

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