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LOGO
CECS 4100
R. Christensen
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.

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.
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.

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.

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

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
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

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)
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
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
Programming in LOGO

What would happen here?
 TO
SQUARE
 REPEAT 4[FD 50 RT 90]
 SQUARE
 END
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
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
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
Programming in LOGO

LOGO Music
 Command
is TONE followed by 2 inputs - one
is frequency (pitch) and the second is duration
 TONE 300 60
 Procedure for music might be
 TO
SONG
 TONE 252 56
 TONE 349 56
 TONE 365 56
 END
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