7-8 Digital Technologies: Designing and tracing algorithms Hangman

The 36 key terms

1algorithm

A set of clear steps, in order, that solves a problem or completes a task, like a recipe or morning routine. Each step must be precise so a person or computer can follow it.

2pseudocode

A way of writing algorithms using plain English and common symbols without the rules of any specific programming language, used to plan logic before coding begins

3end if

A closing keyword in VCAA pseudocode that ends an if block; every nested construct uses end followed by its matching keyword: end if, end while, end for

5input

A VCAA pseudocode keyword that accepts a value from the user and stores it in a named variable. Example: input age stores the user's entered value in the variable age

6print

A VCAA pseudocode keyword that outputs a value, variable or expression as a result. Example: print area displays the current value stored in the variable area

7MOD

The pseudocode operator that returns the remainder after integer division. Example: 10 MOD 3 gives 1 because 10 divided by 3 is 3 remainder 1

9AND

A VCAA pseudocode boolean operator that combines two conditions. The overall result is true only when BOTH conditions are true. Example: x > 0 AND x < 10

11IF-THEN-ELSE

A selection structure that runs one set of instructions if a condition is true, and a different set if it is false

12ELSE IF

A keyword that adds another condition to check if the previous IF or ELSE IF condition was false

13nested if

An if block written inside another if block. The inner condition is only checked when the outer condition is true. Indent the inner block and give each if its own end if.

14FOR i FROM 1 TO n

A loop that repeats its instructions a fixed number of times, counting the variable i from 1 up to n

15WHILE condition DO

A loop that repeats its instructions for as long as the given condition remains true, checked before each repetition

16REPEAT ... UNTIL condition

A loop that repeats its instructions and checks the condition after each repetition, so the body always runs at least once

17count <- count + 1

A counter. It adds 1 to a variable each time a loop repeats. Set it to 0 before the loop. An accumulator works the same way: total <- total + x adds a value each time.

18IF inside REPEAT

An IF placed inside a REPEAT is checked again on every repetition, so each pass through the loop can take a different path.

19if x > 0 then for i from 1 to x

A loop written inside an if branch only runs when that branch's condition is true. If the condition is false, the loop is skipped. An else branch can hold a loop too.

20Nested FOR loop

A FOR loop placed entirely inside another FOR loop, so the inner loop runs fully for every repetition of the outer loop

21Mixed iteration

Nesting one loop type inside a different loop type, such as a FOR loop inside a WHILE loop

22sequence, branch, loop

Most algorithms mix steps in order (sequence), decisions (branch) and repeats (loop). When you read an algorithm, you can label each part and explain it in your own words.

23flowchart

A visual diagram that maps a program's logic before coding, using ovals for start/end, rectangles for steps, and diamonds for yes/no decisions

24parallelogram

The flowchart shape for an input or output step, like getting a name from the user or showing a result. Write the action and variable inside, e.g. Input age.

25flowchart sequence

A line of rectangles joined by arrows from the Start oval to the End oval, with one arrow in and one arrow out of each step. Each step is a short action phrase.

26decision diamond

A diamond shape in a flowchart that holds a yes/no question. One arrow labelled Yes and one labelled No lead to different steps, and the paths can join up again later.

27chained decisions

Putting one decision diamond after another, so a No arrow leads to the next diamond. This lets a flowchart choose between three or more paths, and every path reaches End.

28nested decision

A diamond placed on the Yes or No path of another diamond, so the second question is only asked after the first answer. Every path still ends at the End shape.

29flowchart loop

An arrow that goes back to an earlier shape, usually from a decision diamond, so the steps repeat until the exit condition is met and the exit arrow is followed.

30decision inside a loop

A diamond on the loop path is asked on every pass. Both its Yes and No branches rejoin, then go back to the loop test, usually after the counter update.

31flowchart to steps

Changing a flowchart into written steps: a diamond becomes IF or a loop condition, a back arrow becomes REPEAT, then check both versions do the same thing.

32Trace table

A table that records the value of each variable at every step of an algorithm, used to check its logic by hand.

33trace an if

Check the condition using the current values, record TRUE or FALSE in the trace table, then follow only the branch that is true and skip the other branch.

34nested loop

A loop inside another loop. When tracing, the inner loop completes all its repeats for each single repeat of the outer loop, so total passes = outer repeats x inner repeats.

35Execution order

The exact sequence in which an algorithm's lines run, followed step by step to trace its behaviour.

36test data

Chosen inputs, each with the output you expect, picked so every path (branch) through an algorithm gets tested. Compare the real result to the expected output.

37Boundary values

Test inputs at the edge of a condition. For age >= 18, test 17 (just below), 18 (exactly on) and 19 (just above) to check the algorithm picks the right path at the edge.

38bug

A mistake in an algorithm. Follow the steps until the result goes wrong, then fix that step. It might be in the wrong order, missing, or unclear.

39design an algorithm

Start with the user's problem, list the steps the solution must do, then add any decisions and repeats. Think about what the user puts in and needs out, and test the steps with them.