readline在C ++？ [英] readline in C++?

问题描述

我有一个文本文件，我需要读入我的代码中的变量。例如，让我们说 .txt 文件如下：

I have a text file that I need to read in to variables in my code. For example lets say the .txt file looks like:

John
Town
12
Mike
Village
22

其中有一个名称的模式，然后地址，然后多个人的年龄。我发现有（ ` ）

where there is a pattern of name then address then age of multiple people. I found that with (`)

string line;
ifstream myfile ("example.txt");
if (myfile.is_open())
{
    while ( getline (myfile,line) )
    {
      cout << line << '\n';
    }
    myfile.close();
}

我可以打印出文本文件的每一行，将文本转换为变量？
我记得在Java中你可以按照

I can print out each line of the text file, but how could I assign the text to a variable? I remember in Java you could do something along the lines of

while(there is a next line){
    name = something.readline();
    address = something.readline();
    age = something.readline();
    //do something with variables i.e construct new object then 
    //re-loop to construct new object with next set of data
}

诀窍是在readline（）被调用后，它将在文本文件中向下移动一行，然后下一个变量将被分配给下面的文本等等。

the trick was that after readline() was called it would then move down a line in the text file and then next variable would be assign to the text below and so on. How can I recreate this in C++?

推荐答案

当我做这样的事情，我喜欢把我的数据结构成记录和写一个读取每个记录的函数，如下：

When I do stuff like this, I like to structure my data into records and write a function to read each record rather like this:

// logically grouped data
struct record
{
    std::string name;
    std::string address;
    unsigned age;
};

// function to read in one record
// returns std:ostream& so that the while() loop can check
// the stream to make sure the read was successful.
// Takes record as a reference to pass the data back out
// of the function
std::istream& read(std::istream& is, record& r)
{
    std::getline(is, r.name);
    std::getline(is, r.address);
    is >> r.age >> std::ws;
    return is;
}

int main()
{
    std::ifstream myfile("example.txt");

    record r;

    while(read(myfile, r)) // while the read was a success
    {
        // do something with record here
        std::cout << "   name: " << r.name << '\n';
        std::cout << "address: " << r.address << '\n';
        std::cout << "    age: " << r.age << '\n';
        std::cout << '\n';
    }
}

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