Thread: Understanding C++ Online References

That may be a poorly worded title, but this is what I am confused about. The only online reference I use for C++ is this website:

http://www.cppreference.com/

When I look functions up, it doesn't seem to tell me everything that is available. For instance, when looking the transform function here:

http://www.cppreference.com/cppalgorithm/transform.html

this is the prototype:

Code:

#include <algorithm>
iterator transform( iterator start, iterator end, iterator result, UnaryFunction f );
iterator transform( iterator start1, iterator end1, iterator start2, iterator result, BinaryFunction f );

What exactly is UnaryFunction f? I know that a unary function is something that operates on only one member (unlike binary operators addition, multiplication, etc). From other code, I have seen that tolower and toupper work there when operating on strings, but what else is available?

For a day or two I messed around with Windows programming and when searching the MSDN is seemed to explicitly say what options could be placed there. Are there any sites like that are a general C++ reference site and not specific to windows programming?

It seems like the biggest hurdle to programming is understanding the documentation. There certainly isn't a lack of it out there. It's just getting to the point where it all makes sense and you can understand it.

Check this code out:

Code:

// An improved version of the program! ^_^ Good mood...
#include <iostream>
#include <string>

int main (void) 
{

   std::string answer = "twenty";
   std::cout << "How many apples did I buy? (word answers):";
   std::cin >> answer;

   transform(answer.begin(), answer.end(), answer.begin(), tolower);

   if(answer != "twenty")
   {
       std::cout << "Sorry, you're wrong\n";
   }
   else 
   {
       std::cout << "Yes, that's correct\n";
   }
   
   
   std::cin.ignore();
   std::cin.get();
}

One more quick question.
Why does this code work without me including the algorithm header? Is it automatically included with the string header?

Thank you.

I find that reference site to be incomplete anyway. Check out http://www.sgi.com/tech/stl/table_of_contents.html see if it works for you. While it's not as orgaized into subsections as the other one, it has much more information.

Thanks for the help.