Thinking in Steps
Flowchart symbols
Name the four flowchart symbols and choose the right one for a step, a question, a start and an input or output.
A flowchart is an algorithm drawn as a picture. Each step sits in a box, arrows join the boxes to show what happens next, and the shape of the box tells you what kind of step it is. That is the whole idea: you can glance at a flowchart and see its shape before you have read a single word inside it.
The four shapes
An oval marks the start and the stop. A parallelogram — a leaning rectangle — is for reading something in or printing something out. A plain rectangle is a step that does some work. A diamond is a question, and it is the only shape with two arrows leaving it, one marked Yes and one marked No.
Have a play
Each of these shapes has a name — find out what each one is called. Notice that only one of them has corners pointing up and down.
Tap any part of the picture.
Worked example
Which shape holds each step of this flowchart: Start, Read the price, Is the price over 100?, Print the answer, Stop?
Start and Stop both go in ovals.
Ovals are the bookends, and a flowchart with no oval has no obvious place to begin.
Try it together
Now choose the shape for each step of a flowchart that finds whether a number is even.
Answer each one with the name of a shape: oval, parallelogram, rectangle or diamond.
1.The first box says Start. Which shape is it drawn in?
Have a go
Have a go on your own. A box says "Add the two numbers together". Which shape is it drawn in?
Hint: Nothing is being asked and nothing is crossing in or out — work is simply being done.
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.