Commands of ALPLogo programming environment

 

Number

Format of the command

Command explanation and example

1

backward n

Turtle moves back by n dots(pixels).

 

backward 50

2

break

Used to exit the cycle repeat, without waiting for the completion of the cycle.

 

variable x

x = 0

pendown

repeat 1000

[

    forward x right 90

    x = x + 10

    if (x> 350) [ break ]

]

3

clean

Clears working area.

 

clean

4

forward n

Turtle moves forward by n dots (pixels).

 

forward 100

5

go x, y

Turtle goes to point with coordinates (x, y).

 

go 200, 300

6

hideturtle

The command hides the turtle on the screen.

 

hideturtle

7

home

This command returns the turtle

center of the screen and set so that its head is facing up.

home

8

if (condition)

    [command1]

else

    [command2]

If the condition is true, then run

command group command1, otherwise

run command group command2.

 

if (c1 <c2)

    [write "c1 is less"]

else

    [write "c1 is no less"]

 

In some cases there is no requirement to use else command (you do not need to use part else).

9

left n

Turtle turns left on n degrees.

 

left 60

10

music m, s

Playing a melody m at a speed of s.

 

music cücələrim.alm, 80

11

musicstop

Stops playing the melody.

 

music cücələrim.alm, 80

wait 2000

musicstop

12

paint x, y

The screen is painted in the appropriate color, starting from the point with coordinates x, y. If the screen has figures, then the closed area of them do not change color.

 

go 200, 200

pendown

// draw square

repeat 4

[

   forward 100 right 90

]

pencolor 4

// paint square

paint 250, 150

13

pencolor r

Selects pen color r. Here, the variable r can take values from 0 to 15.

pencolor 4

14

pendown

Turtle puts pen to keep track of when it move.

 

pendown

15

penup

Turtle raises the pen, not to

leave a trail when moving.

 

penup

16

penwidth n

Turtle uses the pen thickness n.

 

penwidth 3

17

random(n)

Generate a random integer in range 0 to n-1.

 

write random(100)

18

repeat n

  [commands]

command in brackets [] are repeated n times.

 

repeat 4 [forward 100 right 90]

19

right n

Turtle turns right by n degrees.

 

right 90

20

screenH

System variable indicating the height of the screen (the number of vertical pixels). This variable is not declared in the program.

 

write screenH

21

screenW

System variable indicating the width of the screen (the number of horizontal pixels). This variable is not declared in the program.

 

write screenW

22

showturtle

Command displays the turtle on the screen.

 

showturtle

23

subroutine abc (x, y)

Specifies the helper program (subroutine) that is called from main program. For example:

 

subroutine square (a)

[

    repeat 4 [forward a right 90]

]

 

This subroutine builds a square with part equals a. For the construction of squares with a side of 80 and 100 is sufficient to write in the main program:

 

square (80)

square (100)

24

textsize n

Specifies the text font size n points, where n - integer.

 

textsize n

25

turtleX

System variable indicating the current X coordinate of Turtle (across the screen width). This variable is not declared in the program.

 

write turtleX

26

turtleY

System variable indicating the current Y coordinate of Turtle (across the screen height). This variable is not declared in the program.

 

write turtleY

27

variable x

It declares a variable x.

 

variable a, b

 

declares two variables a and b. For

setting the variable value it uses the sign assignment.

 

a = 5

b = a + 1

28

wait x

Pauses execution of commands by x milliseconds.

 

forward 100

wait 1000

forward 200

29

write x

Writes indicated value of x in the operating field. For writing string characters it needs to be described in quotes.

 

variable a

a = "Hello"

write a

write "Hello"

30

//

The text following these characters is perceived as a comment. Unlike other commands comments do not run.

 

// draw square

Note

In the area code by using the keyboard shortcut CTRL + SPACE (CTRL + Spacebar), you can open a list of commands and using ready-made commands, accelerate the coding.