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A Turtle object has the ability to connect two points with a straight line if, and only if, both points are inside the World object. If a point is outside the world and a turtle attempts to move to it, theturtle will behave like a dog inside a fenced yard running along the fence and barking at someone who is walking along the sidewalk on the other side of the fence. The turtle willmove along the inside boundary of the world. This is indicated by the black horizontal dotted line segments in the upper left and lower right of Figure 3 . In this case, the turtle was trying to reach a point somewhere on the extension of theblack line outside the world.

In comparison, Figure 4 shows the same lines as Figure 3 . The horizontal and vertical scaling were adjusted in Figure 4 to ensure that the end points of all three lines are inside the boundaries of the world. These lines could be drawn by a Turtle object using only the end points of the lines and only two points would be needed for eachline.

Figure 4. Line01 output with different scaling.

Missing image

In general, a turtle is incapable of reliably drawing a straight line betweentwo points if either or both the points are outside the boundaries of the world even though a line between those points would pass through the world. There area variety of ways to deal with this issue. The code that I will present below is only one of those ways.

The driver class named Line01

The driver class named Line01 is shown in Listing 15 . There is nothing new in that code so a detailed explanation should not be required.

The code in the driver class instantiates an object of the class named Line01Runner and calls an instance method named run belonging to that object. The run method is where the action is in the program.

Beginning of the class named Line01Runner

Listing 1 shows the beginning of the class named Line01Runner and the beginning of the method named run .

Listing 1 . Beginning of the class named Line01Runner. class Line01Runner{ //Instantiate the World and Turtle objects.private World world = new World(300,300); private Turtle turtle = new Turtle(0,0,world);//---------------------------------------------------------------// public void run(){//Make the turtle invisible turtle.hide();//Prepare the penturtle.setPenColor(Color.RED); turtle.setPenWidth(2);//Draw the axes in REDturtle.penUp(); turtle.moveTo(world.getWidth()/2,0);turtle.penDown(); turtle.moveTo(world.getWidth()/2,world.getHeight());turtle.penUp(); turtle.moveTo(world.getWidth(),world.getHeight()/2);turtle.penDown(); turtle.moveTo(0,world.getHeight()/2);turtle.penUp(); turtle.moveTo(0,0);

This code fragment is included here strictly for context. There is nothing in Listing 1 that you haven't seen in an earlier lesson.

The method named function for Line01

At this point, I am going to put the run method on hold and explain a method named function . This method is the heart of the program because it evaluates the standard equation of a straight line given by

y = slope*x + yIntercept

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
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Do somebody tell me a best nano engineering book for beginners?
s. Reply
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Devang Reply
are you nano engineer ?
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Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
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What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
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preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
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I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
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