1. Algorithm The key is the step-by-step instructions.
A computer is a machine designed to follow specific instructions very rapidly;
BUT
The computer does only and exactly what it is told.
Computers cannot think!
Computers cannot make assumptions
Copyright © 2008 by Helene G. Kershner

2. Algorithm
An algorithm written so that it can be carried out by a computer is called a program.
To be understood by a computer, the program or algorithm must be written in a programming language.
Copyright © 2008 by Helene G. Kershner

3. Algorithm – Problem Solving Steps
People naturally think at a level of abstraction far too complex for even the most abstract and futuristic computer. Get simple, get “stupid”, make NO assumptions.
Define the problem
Define the output
Define the input
Define the initial algorithm
Refine the algorithm
Define the program
Copyright © 2008 by Helene G. Kershner

4. Algorithm Write an algorithm for tying your shoes.
Copyright © 2008 by Helene G. Kershner

5. Karel the Robot Karel’s World Very limited, 2-dimensional
Made up of Streets that go North and South (vertical)
& Avenues that go East and West (horizontal)
Where a Street and Avenue intersect is a Corner or an Intersection
Streets and Avenues are described by their number, Ex. 3rd Street & 2nd Avenue would just be Street 3 and Avenue 2.
Street 1, Avenue 1, is the origin, or the starting point.
Locations are identified by their street and avenue address or location.
Also contains, walls and beepers
Copyright © 2008 by Helene G. Kershner

6. Karel the Robot beeper wall Karel
Copyright © 2008 by Helene G. Kershner

7. Karel the Robot Karel’s World Karel is a dim-witted R2D2 Walls Beepers
are made of “neutronium”
they are obstacles Karel can see but cannot go through.
Located one half block between streets or avenues
Beepers
are small pinging transmitters
sit at corners and Karel can hear them.
they can be picked up, carried, and put down at corners
Copyright © 2008 by Helene G. Kershner

8. What can Karel do?
Karel does not think. Karel is outstanding at following instruction!
Karel can
move forward (from one corner to the next)
in whatever direction he is facing.
Karel has a compass so he knows what direction he is facing.
Karel has cameras so
he can see the walls
but only when he is half a block away
He has sensors, a mechanical arm, and a beeper-bag
He can hear beepers only if he is on the same corner
He can pick up the beeper and put it in his beeper bag
He can carry the beeper he has picked up from one location to another
He can put take a beeper out of his bag an put it on an intersection.
Copyright © 2008 by Helene G. Kershner