C ++ primer: overload operators and transformations

1. Reload arrow operators:

Class Obj {
Public:
Obj (Screen * p): (new Scptr (p )){}
ScPtr operator-> () {return * ptr ;}
Const ScPtr operator-> () {return * ptr ;}
Private:
ScPtr * ptr;
}

2. Call operators () and function objects

The original name () Is the function call operator! For example, abs ()

In the past, there was a function object, which could look like a function!

The function object is the object that defines the class of the call operator:

Class GT {
Public:
GT (size_t val = 0): bound (val ){}
Bool operator () (const string & s)
{
Return s. size ()> = bound;
}
Private:
Std: string: size_type bound;
}
Usage:
GT (6 );
Count_if (words. begin (), words. end (), GT (I ));