Create a Pen class and integrate it into Turtle

Give the Turtle a pen object to use. The Pen class should have properties color and width and methods Pen(), setColor(), setWidth().

Add a setPen() method to Turtle to handle changing the Turtle’s pen. You will also need to make small modifications to your other code to reflect the fact that the Turtle has a Pen object as a property.

You can now define Pens the Turtle can use.

For example:

thick_red = Pen(); 
thick_red = thick_red.setColor(‘red’); 
thick_red = thick_red.setWidth(5); 
thin_blue = Pen(); 
thin_blue = thin_blue.setColor(‘blue’); 
thin_blue = thin_blue.setWidth(1); 
turtle = turtle.setPen(thick_red); … 
turtle = turtle.setPen(thin_blue); …

This is what I have so far:

classdef Turtle
    %TURTLE Turtle with a pen
    %Turtle with a pen
    properties
        %location of turtle
        x
        y
        %0 is E, 90 is N, 180 is W, 270 is S
        heading
        %pen status
        pen_on_paper
        %pen
        pen
    end
    methods
        function obj=Turtle()
            %make a new Turtle
            obj.x=0;
            obj.y=0;
            obj.heading=90;
            obj.pen_on_paper= true;
            obj.pen = true;
            obj.pen = true;
        end

          function obj=forward(obj,distance)
              %move forward in current heading given distance
              x2=obj.x+distance*cosd(obj.heading);
              y2=obj.y+distance*sind(obj.heading);
              if obj.pen_on_paper
                  %draw line
                  hold on
                  l= line([obj.x x2], [obj.y y2]);
                  l.Color='black';
                  l.LineWidth=1;
                  hold off
                  pause(0.1)
              end
              %update location
              obj.x=x2;
              obj.y=y2;
          end

          function obj = rotate(obj,angle)
              % rotate CCW by given angle
              obj.heading = mod(obj.heading + angle,360);
          end

      function obj = penUp(obj)
      obj.pen_on_paper = false;
      end

      function obj = penDown(obj)
      obj.pen_on_paper = true;
      end

      function obj= Pen(color, width)
          obj.pen= True
      end

      function obj= SetColor()
          obj.pen= color
      end

      function obj= setWidth()
          obj.pen = width 
      end

      function obj = setPen(obj)
          obj.pen= True
      end

      end

My code doesn't run, what should I do to give the color and width properties to my pen class?

end

Answer 1

[Walter Roberson]

Why are you assigning to obj.pen multiple times, especially with different data types? Is obj.pen a color, a thickness, a logical value?

[Estefania Dimas Martinez]

pen is an object used by the turtle and Pen should be a class with color and width properties

[Walter Roberson]

You need to set the proper property of the object, not keep assigning to obj.pen

For example it might be obj.pen.color = color

Answer 2

[David Davis]

In your code you failed to make pen its own class. Pen should be an object like Turtle with its own properties.