Const-based overloading

C + + does not allow the use of the difference between the top-level const to define overloaded functions, such as the following practice will cause duplicate declarations, because a function called a const int can accept an argument of int (implicitly type conversion)

void print (int) void print (const int)//Duplicate declaration, cannot differentiate void print (int*) void print (INT*CONST)//duplicate declaration from void Print (int), cannot be associated with void Print (Int*const) differentiate

But C + + allows it to be overloaded by distinguishing whether the member function is const, for example, there is no problem with the following approach:

Class Screen {public:    //Two different functions, no duplicate declaration of    Void print () const;    void print ();}

The reason this code does not cause problems is that the const here actually contains the underlying const, not just the top-level const (that is, both the underlying const and the top-level const). The following pseudo-code is a more visually descriptive explanation of why a duplicate declaration problem does not occur:

std::string person::getname () const;//the above sentence is equivalent to the statement://std::string person::getname (const person* const);//(Note: actually C + + There is no such form of declaration, but it is easy to understand and can be understood as a declaration of this form)

Const-based overloading