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This article will explain in detail what is the difference between mem_fun and mem_fun_ref in STL. The content of the article is of high quality, so the editor will share it with you for reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

How do you perform the same operation on all objects in the container? The first thing we may think of is to do it in a loop.

For example, there is a class like this:

Class ClxECS {

Public:

Int DoSomething () {

Cout DoSomething ()

However, there are many C++ masters and awesome people will give us a piece of advice, that is: when dealing with the containers in STL, try not to write your own loops.

So, we have to use for_each in the STL algorithm.

First, add the following function:

Int DoSomething (ClxECS * pECS)

{

Return pECS- > DoSomething ()

}

Then we can use for_each to achieve the function we want:

For_each (vECS.begin (), vECS.end (), & DoSomething)

After talking for a long time, it seems to have nothing to do with mem_fun and mem_fun_ref. In fact, all that is said is to lead to mem_fun and mem_fun_ref. When using for_each, what if we don't add the function above?

It's time for mem_fun and mem_fun_ref to make their grand debut. Just use the following line of code:

For_each (vECS.begin (), vECS.end (), mem_fun (& ClxECS::DoSomething))

It is actually the iterator that calls the member function.

Example:

one

List lpw

For_each (lpw.begin (), lpw.end (), mem_fun (& Widget::test)) / / pw- > test ()

two

Vector vw

For_each (vw.begin (), vw.end (), mem_fun_ref (& Widget::test)) / / w.test ()

three

If the member function has parameters: pass in the value, and then bind1st is this

Std::for_each (m_erased.begin (), m_erased.end (), std::bind1st (std::mem_fun (& SocketSet::_replace_with_last), this))

/ / equivalent to this- > _ replace_with_last (iter) / / iter

The difference between the two:

The function and usage of mem_fun_ref is the same as mem_fun, except that:

Use mem_fun_ref when the object entity is stored in the container

Use mem_fun when there is a pointer to the object in the container.

This is the difference between mem_fun and mem_fun_ref in STL. I hope the above content can be helpful to everyone and learn more knowledge. If you think the article is good, you can share it for more people to see.

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