4.1 various calling methods of member

Nonstatic Member Functions( Non static member functions )

Consider the following code ：

float magnitude3d(const Point3d *_this) {
    };
float Point3d::magnitude3d() const {
    };

choice member function There should be no extra burden , Because the compiler has built “member Function instance ” Convert to equivalent “nonmember Function instance ”

Special treatment of names

generally speaking ,member The name of will be prefixed with class name , Form a unique name ：

class Bar {
    public : int ival;}

among ival It may become like this ：ival_3Bar; Why does the compiler do this ？ Consider the following derivation ：

class Foo : public Bar {
    public : int ival;};

Foo Inside the object base class and derived class both ：

class Foo {
    
public:
	int ival_3Bar;
	int ivla_3Foo;
}

No matter which one you want to deal with ival, adopt "name manglin", Can be absolutely clearly pointed out .

virtual Member Functions( Virtual member functions )

If normalize() It's a virutal member function, Then the following call ：

ptr->normalize();

Will be internally transformed into ：

(*ptr->vptr[1])(ptr);

• vptr Represents a pointer generated by the compiler , Point to virtual table
• 1 yes virtual table slot Index value of , Related to nomalize function
• the second ptr Express this The pointer