1. LOGO
CECS 4100
R. Christensen

2. What is LOGO?
LOGO is a modern, procedural programming language based on the artificial intelligence language LISP.
Although appropriate for beginners, it is a highly sophisticated language.

3. What is LOGO? LOGO is a procedural language.
LOGO is an interactive language.
The programmer receives immediate feedback.
LOGO has turtle graphics.
LOGO uses lists as data objects.
Numbers, characters, and words can be manipulated in LOGO.
Lists are compound data structures.

4. LOGO’s Philosophy for Computer Use in the Classroom
Seymour Papert is the Father of LOGO.
His theoretical background comes from the area of artificial intelligence and from the work of Jean Piaget.
Papert believes the computer is best used in education as an “object to think with” rather than a dispenser of information.

5. What is a MicroWorld?
The concept of “microworld” is one Papert used to describe LOGO and LOGO-like environments.
An environment for learning in which children are free to experiment, test, and revise theories, and invent their own activities.

6. Versions of LOGO
Original microcomputer versions were available in 1979 for the TI 99/4 home computer and the Apple II computer.
LCSI LOGO is what we are using
Available for IBM and Apple
Terrapin LOGO for Apple II family
LOGOWriter (LCSI) combines LOGO and word processing

7. Why Use LOGO?
Provides a sound introduction to programming but is more than a programming language
Encourages thinking and problem-solving skills applicable across the curriculum
Debugging
Learning from errors - immediate feedback
Creates an ideal environment for experimenting and learning hypothesis-testing skills

8. Research on LOGO
May facilitate achievement gains in the area of mathematics
May facilitate problem-solving ability
Evidence indicates that LOGO can serve as a powerful tool in encouraging prosocial interaction, positive self-image, positive attitudes toward learning.
In general, evidence suggests that working in pairs is most advantageous for LOGO

9. Programming in LOGO The Primitives commands LOGO “knows” FD (forward)
BK (backward)
RT (right)
LT (left)
HOME (goes to home position)
PU (lifts the pen)
PD (puts the pen down)

10. Programming in LOGO Perspective - sitting on the turtle’s back
Procedures
Teaching the turtle new tricks
TO SQUARE
REPEAT 4[FD 50 RT 90]
END
Procedures are called from the main program

11. Programming in LOGO Using LOGO variables
Allows an assigned value to a variable so the procedure can be used multiple times with different values
TO SQUARE:SIDE
REPEAT 4[FD :SIDE RT 90]
END
Square is the procedure, side is the variable so the square procedure can be used for multiple sizes of squares

12. Programming in LOGO What would happen here? TO SQUARE
REPEAT 4[FD 50 RT 90]
SQUARE
END

13. Programming in LOGO Recursion is an endless loop
Can be stopped if a conditional statement is used
IF :SIDE > 100 STOP
TO SPIRAL :SIDE
IF :SIDE>100 STOP
SQUARE :SIDE
RT 10
SPIRAL :SIDE+5
END

14. Programming in LOGO LOGO numbers, words and lists
LOGO “knows” how to add, subtract, multiply and divide (+,-,*,/)
The command PRINT (3+5)/2*8 will output 32
To indicate the data-type word, type a quotation mark in front of the string
PRINT “Happy Birthday
Output Happy Birthday

15. Programming in LOGO LOGO Lists
A list is a group of words indicated by brackets
PRINT [TODAY IS TUESDAY]
Output TODAY IS TUESDAY
Can teach the computer “how to talk”, how to create sentences and how to write poetry

16. Programming in LOGO LOGO Music
Command is TONE followed by 2 inputs - one is frequency (pitch) and the second is duration
TONE
Procedure for music might be
TO SONG
TONE
TONE
TONE
END

17. Programming in LOGO Using music in procedures and subprocedures
TO MUSIC
REPEAT 5 FIRST
where first is the name of the first part of the song
SECOND
second is the name of the second part of the song
THIRD
third is the name of the third part of the song
END