Iteration

Iteration

By Mr Wilkinson

Learning Objectives

Understand the use of following constructs in programming - Iteration

Lesson Components

• To understand what is meant by iteration.

• To write a program that draws basic shapes using counter-controlled iteration (FOR Loop).

• To adapt a program for the number of times it needs to repeat for a given purpose.

Iteration

Iteration is a process of repeating steps.
It's the final programming construct along sequence and selection.
In programming we use something called "Loops".

​A loop is a programming construct that repeats a block of code until a specific condition is met.

Iteration

"For Loop"

A for loop repeats code for each item in a sequence or a set number of times. Use it when you know how many repetitions you need.

​What will the outcome be if the user enter the number 10?

Iteration

​It keeps repeating what is in the for loop under the it hit's the number we enter, in our case "10"

Iteration

"While Loops"

A while loop repeats code as long as a condition stays true. Use it when you don't know how many repetitions you need.

​What's happening here?

Multiple Choice

Which type of loop would you use for this scenario:

Print "Happy Birthday" exactly 5 times:

• For

• While

Multiple Choice

Which type of loop would you use for this scenario:

Keep asking for a password until the user enters "python123"

• For

• While

Multiple Choice

Which type of loop would you use for this scenario:

Display each name in a list of 10 students

• For

• While

Multiple Choice

What's going to be the output here?

• 2

• 2

  3

  4

  5

  6

• 2

  4

• 2

  4

  6

​New Information

​The turtle module allows you to draw shapes.

• Which shape do you think is code will draw?

• How could we use less blocks of code to draw the same shape.

​New Information

We could have used a "For Loop"

Today's worksheet