Instructor Wang's C ++ operator reloads the conversion function. Lecture 1

Operator function: operator

Operator Overloading:

A. Become a member function

B. namespace functions (youyuan functions)

The following operators cannot be overloaded :::,.,.*,? :

Operators that must be reloaded as member functions: [], (),->, =

Requirements:

A. New operators cannot be introduced.

B. Do not change the number of elements, priority, and combination.

Definition Syntax:

Binary Functions

Value Type operatoe ◎ (type name-form parameter name) function body // member function

Value Type operatoe ◎ (type name and type name) function body // global function

Unary Functions

Value Type operatoe ◎ () function body // member function

Value Type operatoe ◎ (type name-form parameter name) function body // global function

Example program:

# Include <iostream>
Using namespace std;

Class com {
Private:
Int real;
Int img;

Public:
Com (int real = 0, int img = 0 ){
This-> real = real;
This-> img = img;
}

Void com_add (com & x, com & y, com & z ){
Z. real = x. real + y. real;
Z. img = x. img + y. img;
}
 
Com operator + (com x ){
Return com (this-> real + x. real, this-> img + x. img );
}
 
/*
Com operator + (com & x ){
Return com (this-> real + x. real, this-> img + x. img );
}
*/
 
/*
// Warning c00002: returning address of local variable or temporary
Com & operator + (com & x ){
Return com (this-> real + x. real, this-> img + x. img );
}
*/

Com operator + (int x ){
Return com (this-> real + x, this-> img );
}

Friend com operator + (int x, com y );

Void show (){
Cout <real <"," }

};

Com operator + (int x, com y ){
Return com (x + y. real, y. img );
}

Int main ()
{
Com a, B (1, 2), c (2, 3 );
A = B + c;
A. show ();

A.com _ add (B, c, );
A. show ();

A = B + 3;
A. show ();

A = 3 + c;
A. show ();

}

Note: com & operator + (com & x)

Overload operators in class member functions are not allowed to return references, and the "return local variable address" Warning is displayed.

However, the void com_add (com & x, com & y, com & z) function is supported.