Monday, May 6, 2013

Scratch Programming: Lesson 4

Using Variables and Sub-Routines

Who changed their random number guessing program to include a count of how many guesses were used to get the right answer?

What other changes did you make to your program?

Teacher flips a coing while student guesses the answer.
1. Ask, "what do you pick? Heads or Tails?
2. Flip the coin
3. Check the answer

There are three steps required to guess coin flips.  However those major 3-steps are broken down to sub-routines.  In this lesson we will learn how to make the best use of sub-routines.  When we used Light-Bot in our first lesson we used functions to give instructions to the robot.

In this lesson you will create one main program:

When green flag is clicked
Forever loop
When broadcast ___ wait
When broadcast ___ wait
When broadcast ___ wait

Set the broadcast to:
get player choice
flip coin
compare result

Then create sub-routines for each type of broadcast.

When I receive get player choice

You must use the "and wait" command so the computer knows to wait until all sub-routines are completed.  Also ALWAYS use a stop script command.

When I receive flip a coin
set coin flip to pick random 1 to 2
use an if-else command to assign the numbers to either heads or tails

When I receive compare results sub-routine
Use an if-else command so the program can decide if the answer was correct.

 Finished program is below:

Extension Activity:
Make a new game.  This time the game is Rock, Paper, Scissors.  The program will be same as above but instead of only 2 random answers (heads or tails) there is a possibility of 3 random answers.

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