I was always confused about header files. They are so strange: you include .h file which doesn't include .cpp but .cpp are somehow compiled too.
NOTE: I UNDERSTAND EVERYTHING ABOUT THE HEADERS, PLEASE DON'T TELL ME I'M STUPID OR SHOULD USE OTHER LANGUAGE

Recently I joined a team project, and of course, both .h and .cpp are used.
I understand that this is very important, but I can't live with copy-pasting every function declaration in each of multiple classes we have.

How do I handle the 2-file convention efficiently?
Are there any tools to help with that, or automatically change one file that looks like example below to .h and .cpp? (specifically for MS VC++ 2010)

class A
{
...
    Type f(Type a,Type b)
    {
        //implementation here, not in another file!
    }
...
};

Type f(Type a)
{
     //implementation here
}
...