ACARA Digital Technologies Years 7–8 Definitions Worksheet: Programming with Control Structures and Functions (JavaScript) (Modules 624–634)
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Key terms
Write what each term means, in your own words.
1
ReferenceError
2
TypeError: Assignment to constant variable
3
logic error
4
off-by-one error
5
console.log("total:", total)
6
trace table
7
// console.log(total);
8
console.log("expected 25, got", square(5))
9
predict, change, run
10
debugging
Answer Key
ACARA Digital Technologies Years 7–8 · Modules 624–634 · Student wording will vary for definitions
1ReferenceError — An error shown when code uses a variable or function name that has not been declared, often from a typo, wrong capital letter, wrong scope or using it before declaring it.
2TypeError: Assignment to constant variable — The error JavaScript shows when code tries to give a new value to a const variable. Fix it by declaring the variable with let if its value needs to change.
3logic error — A mistake that lets the program run with no error message but gives a wrong result, such as using > instead of >=, the wrong operator, or steps in the wrong order.
4off-by-one error — A loop bug where it runs one pass too many or too few, caused by a wrong start value or mixing up < and <=. For example, i starting at 0 with i <= 5 runs 6 times, not 5.
5console.log("total:", total) — Prints a labelled variable value while the program runs, so you can spot the line where the value first goes wrong. Remove these debug lines once the bug is fixed.
6trace table — A table with one row per loop repeat, showing the counter, other variables and any output, filled in by hand until the condition is false.
7// console.log(total); — Putting // in front of a line makes JavaScript skip it, so you can switch code off to find a bug. Remove the // to switch it back on.
8console.log("expected 25, got", square(5)) — Test a function by calling it with chosen inputs, logging the actual result next to the expected value, then recording pass or fail. Retest after any fix.
9predict, change, run — Read the code and predict what it does, change one small part (a value, condition or message), run it, then compare the result with your prediction.
10debugging — Finding and fixing bugs: run the program, read the error or compare wrong output with what you expected, find the faulty line, fix one thing, then rerun to retest.