1. An Introduction to Control Structures

2. Introduction to Control Structures
All computers programs, no matter how simple or how complex, are written using one or more the three basic structures
Sequence
Repetition
Selection

3. The Sequence Structure
Follows each instruction in order
Beginning at the first and ending with the last.
You will find sequence structure in all programs.

4. The Sequence Structure

5. Algorithm
The step-by-step instructions that accomplish a task.

6. The Repetition Structure
Directs the computer to repeat one or more instructions until some condition is met.
Write the instructions the following
Repeat XX times walk

7. The Repetition Structure

8. What If
What if you don’t know precisely how many steps there are between Rob and the Chair?
In this case, you simply need to change the condition.

9. The Repetition Structure

10. The Selection Structure
Make Decisions
Driving a Car into the Intersection
The Selection Structure alerts the computer that a decision needs to be made.
Provides the appropriate action to take based on the result of that decision.

11. The Selection Structure