MATLAB Object-Oriented Programming

The set.Radius method tests the value assigned to the Radius property to ensure the

value is not less than zero. MATLAB calls set.Radius to assign a value to Radius.

(“Property Set Methods” on page 8-56.

function obj = set.Radius(obj,val)

if val < 0

error('Radius must be positive')

end

obj.Radius = val;

end

The CircleArea class overloads the plot function. The plot method uses the

rectangle function to create a circle and draws the radius. (“Overload Functions in

Class Definitions” on page 9-34

function plot(obj)

r = obj.Radius;

d = r*2;

pos = [0 0 d d];

curv = [1 1];

rectangle('Position',pos,'Curvature',curv)

line([0,r],[r,r])

text(r/2,r+.5,['r = ',num2str(r)])

axis equal

end

The CircleArea class overloads the disp function to change the way MATLAB displays

objects in the command window.

function disp(obj)

rad = obj.Radius;

disp(['Circle with radius: ',num2str(rad)])

end

end

methods (Static)

The CircleArea class defines a Static method that uses a dialog box to create an

object. (“Static Methods” on page 9-32

function obj = createObj

prompt = {'Enter the Radius'};

dlgTitle = 'Radius';

rad = inputdlg(prompt,dlgTitle);

r = str2double(rad{:});

obj = CircleArea(r);

end

5 Class Definition—Syntax Reference