1. Big problem  small steps
Top Down Design
Big problem  small steps

2. We have a problem!
Making a video game or making a small program Mr. Hastings has asked you to make, every program solves some problem
Starting with a big picture idea (“This is what I want to make”). What do you want to happen?
Take that big problem and break it into smaller steps
Take those smaller steps  break into manageable steps.

3. Outline = A Plan
Now that we know what specific tasks we need to accomplish before solving our problem we have a plan of action.
Just like building a house, some steps are necessary to complete first before doing anything else (drawing blueprint for house, getting permits, hiring contractors, etc…)
Just like building a house, some steps are independent of others (painting once walls are up, independent of landscaping outside)

4. Rock Paper Scissors game
Let’s use our RPS game program as an example: Top down design begins with a BIG PROBLEM (I want to make a game) Breaks that down into sections (I will need to keep score… I will want to know who wins a match… I want some sort of dialogue in the game) Let’s look at what we did as a class with our game design:

5. Tasks:
We need to use the random function. We want the computer to be both unpredictable and unbiased [it won’t cheat]
Create a list of possible choices [rock, paper, or scissors]
Human chooses a R,P, or S
Computer chooses randomly between R,P, or S

6. Tasks Define a function recognizing user’s input
We don’t want to have to repeat typing code  create a game function (asks What your choice is, chooses, then evaluates and repeats)

7. Tasks There needs to be an order / timing (control flow) for gameplay
Human chooses first
Computer chooses second
Choices are compared / evaluated
If human chooses ‘R’ and comp chooses ‘P’: comp wins…
If human chooses ‘P’ and comp chooses ‘S’: comp wins…
If human chooses ‘S’ and comp chooses ‘R’: comp wins…
Else: HUMAN WINS!!! 
Winner declared
Win recorded / counted

8. Tasks
Rules! What beats what?
R > S
P > R
S > P

9. Tasks Win is recorded Keeping Score! How will we know who wins
User win or computer win
After x wins, computer or human wins match (best of x matches)