Programming and Graphics

164 Introduction to C++ Programming and Graphics

string readcolor(bool Iprint) const;

void changecolor(string newcolor);

private:

string color, shape;

float size;

};

The functionpackagenow has access tocolor,shape,andprice. We will
implement this function as:

//--- FRIEND FUNCTION

void package(fruit item)

{

if(item.size<1.0)

cout << "box" << endl;

else

cout << "crate" << endl;

}

We may then state in the main program:

fruit watermelon("green", "oval", 12.0);

package(watermelon);

The second statement will print on the screen:

box

We recall that, if we want to disclose a private field of an object toall
non-member functions, we must declare it as public.

Problems

6.6.1.Implement a friend function that determines whether the color of a fruit
is green.

6.6.2.Implement a friend function that determines whether the size of a fruit
is less than 3.0 inches.

6.7 Circlesandsquares..........................

To further illustrate the concept of private variables, we consider a code defining
two classes, one containing circles and the second containing horizontal squares.