• We are saving all of of our work for this topic into a PowerPoint, that we started two weeks ago.

• You have two options

  1. If you were here last week or the week beofre then open the PowerPoint that you saved your work into and add a new slide for Lesson 4.
  

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Don't for get to create a lesson 4 button on the menu page and add a hyperlink to it!

Subroutines

In computer programming, a subroutine is a sequence of program instructions that perform a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed.

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A 'Flash' subroutine

Below is a flowchart for our lighthouse which shows us how we can use a subroutine to make the lighthouse lamp flash by reusing the same flowchart.

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Using the flowchart above create a subroutine called 'flashes' which makes the lighthouse lamp flash, see what the addition of the number below to our subroutine does to our mimic.

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Add a screenshot of your completed flowchart into your PowerPoint?

Think about the things that happen at a pedestrian crossing when someone crosses the road. The green lights and red man stay on until the cross button is pressed – but what else happens? What are the steps that happen after the cross button is pressed?

Watch the video and create an algorithm by clicking on the pelican crossing image below to download the file and then fill in the blanks.

• Create a subroutine to control only the flashing lights
• Use the Sub option with a Start / Stop symbol
• Refer to the Zebra Crossing mimic solution
• Call the subroutine from the main program

Summing it all up

Lets look at the learning outcomes and decide which one best describes our current level of understanding :

Tick the one you feel is closest to your level