Earlier you used the four steps of computational thinking to break a build down and make it. One of those steps was algorithms: writing the steps of a solution in order.

Today you learn two ways coders write an algorithm down before they touch a block: pseudo-code (plain steps in order) and a flow chart (the same plan drawn as boxes and arrows). You will plan a small quiz, then build it in Scratch and check the program matches the plan.

An algorithm is a clear set of steps that solve a problem. Coders write it down before they build, so anyone reading the plan knows exactly what should happen.

Today you will write the same plan two ways: as a words plan and as a shapes plan.

• Pseudo-code is the words plan: plain words, one step per line. Not a real programming language, just precise enough that someone else could follow it.
• Flow chart is the shapes plan: the same plan drawn as shapes and arrows. An oval starts and ends it, rectangles are actions, and a diamond is a yes-or-no decision.

Here is the plain-English idea you will plan and build today:

A sprite asks for a name and greets them. It then asks how many counties are in Ireland. If the answer is 32, the score goes up by 1 and it says "Correct!". If not, it says "Not quite".

Here is that idea as sample pseudo-code you can imitate:

1. START
2. SET score to 0
3. ASK for a name
4. SAY hello using the name
5. ASK how many counties are in Ireland
6. IF the answer equals 32 THEN
7. change score by 1
8. SAY Correct!
9. ELSE
10. SAY Not quite
11. END

The shapes plan draws these same steps in the same order. The one line that becomes a diamond is line 6, the yes-or-no check: yes goes one way, no goes the other. Your teacher will draw this shapes plan on the board as you talk through it.

And here is the same plan as Scratch blocks. Read it against the pseudo-code above, line for line — every line has a block:

Turn the quiz idea into a plan on paper or in a notes file. Use the sample as a model.

1. Write the pseudo-code. Write the quiz as ordered steps. Every action and every decision needs its own line. You must include SET score to 0, the counties question, the check for 32, the score change, and both messages. Include the name and greeting as well if you can.
2. Draw the flow chart. Redraw the same plan as shapes and arrows. Use an oval for start and end, rectangles for actions, and a diamond for the yes-or-no check on the answer. Label the arrows out of the diamond with yes and no.

1. Get something running early. As soon as you have at least two solid pseudo-code lines (for example SET score and ASK name), open a new Scratch project and place those blocks so something already runs. Come back to finish the rest of the plan, then add the remaining blocks in the next step.