Thread: Are there other string classes?

Hi, I'm getting pretty sick of char * and all other things C++ fail with when I need to type in and store some text. All I want is no extra characters. No flushing buffers, cin.ignore() and things. No keeping track of what works when, ever! However, I do need to be able to convert back to c-strings because i use the strings with winsock-functions like send and recv.

So are there any classes that succeed with the complicated task of reading user input and storing it in an unchanged form?

PS the built in sring-class sucks too

Code:

std::string line;
std::getline(std::cin, line);

No extra characters. No flushing buffers.
You will not be able to escape keeping track of if it worked or not, however.
Also supports converting it back to a C-style string.

If you need a specific type of data, then I have posted an input class on the board that pretty much handles it all for you.

Originally Posted by tabstop

So, then the question becomes, what's wrong with the built-in string class? It sounds like all your problems are input-related, which means you should probably be using more better input commands, like getline, instead of trying to use <<.

I've used all there is. Sometimes one method works, sometimes another does. Sometimes I have to add cin.ignore() here and there, sometimes i don't need too. Thing is, I don't want to be forced to keep track of this anymore. I want one function read(mystring); that reads from my keyboard to mystring until I hit enter. And it would be nice if it worked flawlessly every time.

Elysia, ok that works. But not always when used mixed with cin.get(). Maybe I've blamed the string-class because cin.get screws it up.

Yes, it is. Best not to mix them, or you will run into the same problem again.

It seems to me that std::geline and cin.get() get along just fine. It's operator>> that's guilty of leaving stuff into the buffer (I guess that has some purpose though, so you can for example see what the delimiter was).

Ah yes, my bad.

In any case you don't need a new class. Perhaps wrapping the input functions up in functions that automatically clean the buffer is enough?

Originally Posted by tabstop

So, then the question becomes, what's wrong with the built-in string class?

It is a monolithic class

(Though technically it is not "built-in" since it is part of the standard library, not the core language, but anyway finnepower did not have Herb Sutter's view in mind with that comment.)

Originally Posted by anon

Perhaps wrapping the input functions up in functions that automatically clean the buffer is enough?

Yes, that sounds like a viable approach to me. Simply not mixing formatted input functions with get() and getline() is not always the best solution, in my opinion, since on occasion you may want to use both.

You are wise, laserlight.

It often seems like guesswork to me as to when I'll need an ignore(). Does this always blast past the user?

Code:

std::cin >> type; //user makes a '\n' to indicate entry
cin.get(); //maybe the buffer is empty and we'll wait... maybe there's an extra \n and we won't?

For me, cin consistently leaves the delim in the stream. I can't seem to find the sentence in Stroustrup that clarifies this.

Originally Posted by CodeMonkey

It often seems like guesswork to me as to when I'll need an ignore(). Does this always blast past the user?

What happens if the user input has trailing whitespace? One way is to simply ignore as many characters as possible that may be left in the buffer until and including the next newline character:

Code:

std::cin >> type;
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

Another way is to specifically extract and discard whitespace:

Code:

std::cin >> type;
std::cin >> std::ws;

Code:

std::cin >> type;

My input class performs this beautifully without the need to worry for cleaning the input.
So if that sort of thing is what you need, I may have the solution wrapped inside a class, which I posted some time ago.