IGCSE Computer Science Paper 2 Definitions Worksheet: 7a Program Development Life Cycle (Modules 83–92)
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Key terms
Write what each term means, in your own words.
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Trace table INPUT
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Counter ← Counter + 1
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IF Mark >= 50 THEN
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FOR Count ← 1 TO 5
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WHILE and REPEAT loop trace
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Count ← Count + 1
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Tracing a validation loop
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trace table
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first wrong value
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PDLC
Answer Key
IGCSE Computer Science Paper 2 · Modules 83–92 · Student wording will vary for definitions
1Trace table INPUT — A prompt is written in the OUTPUT column. The value the user types for an INPUT is written in that variable's column on that step, taken from the test data.
2Counter ← Counter + 1 — When tracing, work out the right side using the current values, then write the result in that variable's column. The old value is used first, then replaced by the new one.
3IF Mark >= 50 THEN — To trace an IF, work out if the condition is TRUE or FALSE for the current values, then follow only the THEN or ELSE path. Skipped statements get no row in the trace table.
4FOR Count ← 1 TO 5 — To trace a FOR loop, give the loop variable each value from start to end in turn, run the loop body once for each value, and record every pass in its own row of the trace table.
5WHILE and REPEAT loop trace — Trace a loop by testing its condition each pass: WHILE tests before the body and may never run; REPEAT tests after the body so runs once at least. Stop when the loop ends.
6Count ← Count + 1 — Trace table for counting and totalling: Count and Total start at 0 in the first row, change each pass (Count only if the IF is true), and the final values are output after the loop.
7Tracing a validation loop — Step through a validation loop with valid and invalid inputs, recording each rejected value, the error message output and the value finally accepted in a trace table.
8trace table — A table for a dry run: follow the algorithm line by line with the given inputs, writing each variable, output and prompt in the order it happens, then check the final values.
9first wrong value — In a trace table, the first row where a value differs from what you expected points to the faulty line of the algorithm. Look at that line, then suggest a correction.
10PDLC — Program development life cycle: analysis, design, coding, testing. Apply it to a scenario by saying what is done at each stage and which methods and test data are used.