Paper 2 scenario practice

File-based score statistics

The scenario

A teacher has saved student test scores in a text file called "scores.txt". Each line of the file contains ONE score (an integer between 0 and 100). The teacher wants a program that: 1. OPENS "scores.txt" for reading. 2. Reads each line until the END OF FILE, accumulating: the COUNT of scores, the TOTAL of all scores, and the MAXIMUM score seen. 3. CLOSES "scores.txt". 4. Computes the AVERAGE = total / count (only if count > 0). 5. OPENS a different file "summary.txt" for writing. 6. WRITES three lines to it: the count, the average, and the maximum. 7. CLOSES "summary.txt". 8. If the input file was empty (count = 0), output a message instead of writing the summary file. Use Cambridge file-handling commands: OPENFILE, READFILE, WRITEFILE, CLOSEFILE, and the EOF() function. Write a program in pseudocode (or a high-level language of your choice). Marks will be awarded for correct file open/close, EOF-controlled reading, accumulating statistics, and writing to the output file.

Lessons that prepare for this: Lesson 19 — Pseudocode and flowcharts · Lesson 23 — Programming concepts · Lesson 26 — File handling

Marking scheme — total 15 marks

Cambridge IGCSE 0478 Paper 2

2
Open input file and initialise totals: OPENFILE "scores.txt" FOR READ. DECLARE the variables (score, count, total, max) and initialise count ← 0, total ← 0, max ← -1 (or 0) so the first comparison sets it correctly.
4
EOF-controlled read loop: WHILE NOT EOF("scores.txt"): READFILE "scores.txt", score. Accumulate count and total. IF score > max THEN max ← score. The loop stops when EOF is TRUE.
2
Close input and compute average: CLOSEFILE "scores.txt" after the loop. IF count > 0 THEN average ← total / count — guards against divide-by-zero.
2
Empty-file fallback: IF count = 0 THEN OUTPUT a message saying the file was empty AND skip writing the summary file. The empty case must not crash the program.
3
Write summary file: ELSE branch: OPENFILE "summary.txt" FOR WRITE. WRITEFILE three lines (count, average, max). CLOSEFILE "summary.txt". File must be opened and closed correctly.
2
Program structure and naming: WHILE/ENDWHILE properly paired; IF/ENDIF visible; clear identifiers (count, total, max — not c, t, m).

Hints — reveal one at a time, only if stuck

Your pseudocode workspace

1 line