Using / returning an iterator

[kribel]

Hi all,

I just read the iterator reference at cplusplus.com and a chapter about iterators in a book, but I still cannot get the point about them.

Here is my code snippet followed by the question.

#include <iterator>
#include <string>

using namespace std;

class Status
{
	private:
		bool stat;
		
	public:
		Status()
		{
			stat = false;
		}
		
		bool getStatus() const
		{
			return stat;
		}
		
		void setStatus(bool stat)
		{
			this->stat = stat;
		}
}


class myClass
{
	private:
		Status stat;
	
	public:
		myClass(){};
		
		Status& getStatus() const
		{
			return stat;
		}
}


int main(void)
{
	myClass var();
	
	var.getStatus().getStatus();
}

In myClass I would like to return a reference of the Status class. Because of the const in line 37 the code does not work.

That is the point where I would like to use an iterator. I just dont't know how. I got to the point to use the iterator template, but that is it.

iterator<Status, input_iterator_tag> it_Status;

But what shall I do after that? How can actually return an iterator and access the methods of the Status class.

It would be great if some of you could help me on that topic.

[ciphermagi]

Iterators are for containers, this doesn't look like it would apply here. You could try returning a pointer if you want.

[Peter87]

Why do you want to use iterators here? It sounds like you don't understand what iterators are for. Iterators are used to iterate over the elements in a container.

[vlad from moscow]

You should write

		const Status& getStatus() const
		{
			return stat;
		}

and in main

var.getStatus().Status::getStatus();

Also you shall place ; after a class definition.

And as for iterators they are used with containers or sequences. You need no iterator in your code.

[Peter87]

@vlad what is the advantage of doing var.getStatus().Status::getStatus();
compared to just var.getStatus().getStatus();?

[clanmjc]

There a couple of simple solutions to your current problem and like the others said you don't need an iterator here. Because you are returning a reference and you have declared getStatus as const, it automatically returns the Status& as a const and it is complaining that it cannot convert from const Status& to Status&. You can either change the return value to be a const Status& or const cast away the constness (In your case I would not do).

In other words, when you call a const member function, whether the object is const or not, it treats it as if this is const, you can verify this by calling a const member function from a non cost object and looking at the 'type' of the 'this' pointer, it will be a const * to a const 'whatever my object type is'

As a side note: Do you really want to return a static reference here in the first place? By returning a reference you are now exposing your private data that is Status. If what you really want is just to get the "status' status" then might I suggest this alternative, still adhering to the encapsulation of MyClass.

class myClass
{
   //... Stuff in myClass
    bool getStatus() const
    {
      return stat.getStatus();
    }
   //...
}

// Now main would look like this...

main()
{
  myClass var;
  var.getStatus();
}

[vlad from moscow]

@vlad what is the advantage of doing var.getStatus().Status::getStatus();
compared to just var.getStatus().getStatus();?

Because it is a bad idea to use the same name for two functions defined in class and in its member. So for selfdocumentation i inserted class name before the second call of the function.

[kribel]

Many thanks to all of you.

@clanmjc:
I know that I am exposing private date here. But this is just an example.