Reading constant number of characters in C++

How would you read a string if it was no longer than 20 characters and could contain spaces in C++? For example I have this kind of file:

3
Namama               4 5 12
Cool                 4 2 34
Not So Cool          4 2 45

I want to write it in the most basic way possible. And I would prefer using only C++ (no C thingies) in this case. This means I want to store it in std::string.

I could use istream::get or istream::getline but then I have to avoid the new line characters. This is problematic (and the code I'm writing is going to be shown to beginners).

What are your solutions for this problem?

Edit:

As asked I'm going to tell you what I have tried but I don't think it's going to be any good. I am not a C++ beginner and usually I would have used something like istream::get and char array but removing new line characters might seem too techy for some people.

So... Either reading char array or std::string using istream::operator>> fails because it stops reading when they see space character (and I may have to read several words). This means the following code fails:

char name[21];
std::cin >> name;

or...

std::string name;
std::cin >> name;

Another thing is that new line characters differ from system to system and actually Windows use two of them by default and I have tried 开发者_JS百科using istream::ignore with 2 as an argument on Windows and that was the only way to ignore the new line and I came to conclusion that it's because Windows use two characters for a new line mark. That means it wouldn't work on Linux and it would have to be more complex... Again - bad for beginners.

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If you want to read exactly 20 characters,

for(int i=0; i<3; ++i) {
    std::string result;
    int one, two, three;

    result.resize(20);
    if (!std::cin.read(&result[0], 20)) throw std::runtime_error("reading buffer failed!");

    if (!std::cin >> one >> two >> three) throw std::runtime_error("reading numbers failed!");
    if (!std::cin.ignore(1000, '\n')) throw std::runtime_error("ignore failed!");
}

If you don't want exactly 20 characters, how do you know when you've reached the end of the string?

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One way to accomplish this would be to use istream::read into a temporary buffer of sufficient size, and then use that buffer to initialize a std::string.

char name[21];
std::cin.read(name, 20);
std::string nameString(name); // If you want it in a std::string

This reads exactly 20 characters, newlines and everything. If it's for an exercise, then this is at the very least very simple. If you sometimes want less than 20 characters, it is possible to determine how many extra were read and back the get pointer by std::istream::unget or equivalent.