Thread: Turtle Graphics, how does it work?

The Problem:

Code:

 ( Turtle Graphics ) The Logo language, which is popular among elementary school children, made the concept of 
turtle graphics famous. Imagine a mechanical turtle that walks around the room under the control of a C++ program.
 The turtle holds a pen in one of two positions, up or down. While the pen is down, the turtle traces out shapes as it 
moves; while the pen is up, the turtle moves about freely without writing anything. In this problem, you will simulate
 the operation of the turtle and create a computerized sketchpad as well.

Use a 20-by-20 array floor that is initialized to zeros. Read commands from an array that contains them. Keep track
 of the current position of the turtle at all times and whether the pen is currently up or down. Assume that the turtle
 always starts at position (0, 0) of the floor with its pen up. The set of turtle commands your program must process 
are shown in Fig. 7.33.


Figure 7.33. Turtle graphics commands.

1
 Pen up
 
2
 Pen down
 
3
 Turn right
 
4
 Turn left
 
5,10
 Move forward 10 spaces (or a number other than 10)
 
6
 Print the 20-by-20 array
 
9
 End of data (sentinel)
 




Suppose that the turtle is somewhere near the center of the floor. The following "program" would draw and print a 
12-by-12 square and end with the pen in the up position:

2
5,12
3
5,12
3
5,12
3
5,12
1
6
9



As the turtle moves with the pen down, set the appropriate elements of array floor to 1's. When the 6 command 
(print) is given, wherever there is a 1 in the array, display an asterisk or some other character you choose. 
Wherever there is a zero, display a blank. Write a program to implement the turtle graphics capabilities discussed 
here. Write several turtle graphics programs to draw interesting shapes. Add other commands to increase the 
power of your turtle graphics language.

I have no idea how it will work. Is it like snake, but instead you have to draw? Or you just have to type the coordinate like in a graph? I just cant visualize it