Thread: List of Include functions

Originally Posted by carlorfeo

so is it possible that another compiler won't find <string> if I didn't include it in my source?

Yes, that's exactly right.

The compiler might not find std::string. It won't even search for <string>, which is a header, unless you include it.

Exact notation is important in net-based communication.

In my opinion, learning how to implement e.g. a linked list should happen before learning "ready-to-use" c++ lists or such containers. They are very useful, but a beginner will probably use them in a wrong way (like I did myself with strings), if he doesn't understand how they exactly work.

Logically, that means that you should learn how to implement the stuff in <iostream> before you write your first "hello world" program.

After all, a beginner will probably use std::cin and std::cout in a wrong way if he does not understand how they exactly work.

But this is putting the cart before the horse. Clearly, "hello world" programs are popular introductions to programming languages because they teach basic syntax and how to write some output to the console.

The next step is often a program that accepts input, say a variant of "hello world" with a personalised greeting. This teaches about basic input, and yet even at this point there is no mention that from the previous lesson, std::cout is a std::ostream which is a typedef for std::basic_ostream<char> which is a subclass of std::basic_ios<char, std::char_traits<char> > which is a virtual base... at which point no one wants to learn C++ any more because it is just too hard, but we have not even mentioned std::ios_base yet, much less talked about how to implement these class templates.

Ok, no matter. Everybody have to choose the right way himself, due to his own experience.
So my opinion is not against yours, it is just a different point of view.

Your own experience shows that learning how to use something first is often easier than learning how to implement it first, as I have pointed out with iostreams. Likewise, as advocated by Koenig and Moo in their book Accelerated C++, learning how to use std::vector before introducing arrays and pointers is usually a better pedagogical technique than teaching arrays and pointers first.

For instance, it would be uselessly expensive to create a string just to pass a single character to a function.

This has nothing to do with how strings work internally, and everything with understanding the concept of a string and the concept of a single character. Which is probably more difficult if English isn't your native language.

I said the opposite instead: I said that using <iostream> stuff would be enough for a c++ beginner.

That's my point: you believe, and rightly so, that <iostream> is enough for a beginner. Likewise, <vector> and <string> is enough for a beginner, until enough knowledge is gained to use the low level facilities that these classes abstract away.

In my case, I prefer to start from the harder things and then, once I got them, make my life easier using available tools.

But <iostream> makes life easier for us. If you prefer to start from the harder things, then why start by using std::cin and std::cout? Why not start by implementing them yourself, or by programming a GUI?

Too late. You already used them.