Const member functions

This paper concludes:

A const object, a pointer to a const object, or a reference can only be used to invoke its const member function.

Example Description:

classa{ Public:    voidMf1 () {cout<<"Function Call"<<Endl; }    voidMF2 ()Const{cout<<"Const Function Call"<<Endl;}};intMain () {a A;     A.MF1 (); //OKA.mf2 ();//OK    ConstA B;    B.MF1 (); //ErrorB.mf2 ();//OK    return 0;}

Listen to the this pointer should know that two member functions of the declaration is actually this:

void mf1 (A *constthis); void mf2 (const A *constthis);

(Each member function has an additional, implicit parameter, this, which binds the member function to the class object that called the function)

It is also illegal to bind a generic reference to a const object because of C + + rules.

Const int 1024x768 ; int &refval = ival;    // Error

So the proof.

Const member function