Module 2 – BASIC — build and test
Collections and repeated work
15-minute session: read for 3 minutes, trace for 3, experiment for 7, and complete the check for 2. Spend longer whenever you need.
A collection stores related values. The loop visits 1, 2, and 3, updating the total from 0 to 1, then 3, then 6. Record this trace rather than guessing. Identify the first and last valid positions in this language: Pascal can declare a 1-based array, while many other examples use zero-based containers. Add another value and update the bounds correctly. Explain what an empty collection should produce.
Line numbers describe program order. GOSUB visits a subroutine and RETURN resumes the caller. SYSTEM exits this interpreter. BASIC dialects differ: a 6502 or Z80 computer does not automatically run this exact dialect.
10 DIM M(3)
20 LET M(1)=1
30 LET M(2)=2
40 LET M(3)=3
50 LET T=0
60 FOR I=1 TO 3
70 LET T=T+M(I)
80 NEXT I
90 PRINT T
100 SYSTEM
Expected result: 6
Practice and evidence
Keep three notes: your prediction, the actual result, and why they match or differ. The completion check grades understanding; the practice task builds skill.
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