将行拆分为整数 [英] Splitting up lines into ints

问题描述

我有一个从中读取的文件，它包含一堆行，每行都有不同数量的整数，我无法将其拆分为整数向量的向量.

I have a file that I read from, it contains a bunch of lines each with a different number of integers, I'm having trouble splitting it up into a vector of a vector of ints.

这是我当前的代码.

std::vector<int> read_line()
{
    std::vector<int> ints;
    int extract_int;
    while((const char*)std::cin.peek() != "\n" && std::cin.peek() != -1)
    {
        std::cin >> extract_int;
        ints.push_back(extract_int);
    }
    return ints;
}
std::vector<std::vector<int> > read_lines()
{
    freopen("D:\\test.txt", "r", stdin);
    freopen("D:\\test2.txt", "w", stdout);
    std::vector<std::vector<int> > lines;
    while(!std::cin.eof())
    {
        lines.push_back(read_line());
    }
    return lines;
}

问题是所有整数都被当作一行读取.

The problem is that all of the ints are being read as a single line.

我做错了什么?

推荐答案

问题在于您的 (const char *)std::cin.peek() != "\n" 演员表.演员是邪恶的；尽量避免使用它们.以下代码有效:

The problem is your (const char *)std::cin.peek() != "\n" cast. casts are evil; try to avoid using them. The following code works:

std::vector<int> read_line()
{
    std::vector<int> ints;
    int extract_int;
    while(std::cin.peek() != '\n' && std::cin.peek() != -1)
    {
        std::cin >> extract_int;
        ints.push_back(extract_int);
    }

    std::cin.ignore(); // You need this to discard the \n

    return ints;
}

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