Build reports from records and text files

Choose a record for related fields

A product code is STRING because leading zeroes may matter. Its quantity is INTEGER because it is counted. A record keeps these fields under one identifier; an array stores several products.

Read files without losing the final line

Open for READ, test EOF before reading, process each successful read, then close. Convert a numeric STRING only after validation. An empty file is a legitimate test, not an error in the problem.

OPENFILE "demo.txt" FOR WRITE
WRITEFILE "demo.txt", "4"
WRITEFILE "demo.txt", "7"
CLOSEFILE "demo.txt"
DECLARE Line : STRING
DECLARE Total : INTEGER
Total ← 0
OPENFILE "demo.txt" FOR READ
WHILE NOT EOF("demo.txt") DO
    READFILE "demo.txt", Line
    Total ← Total + STR_TO_NUM(Line)
ENDWHILE
CLOSEFILE "demo.txt"
OUTPUT Total

This self-contained demonstration creates its own file. In a question where the file already exists, do not open it for WRITE: that would erase the data.

The checker supplies sales.txt, one numeric integer string or invalid text per line. Output the count of numeric lines, then their total. Ignore invalid lines. Close the file.

DECLARE Text : STRING
DECLARE Count, Total : INTEGER
Count ← 0
Total ← 0
// Open, read safely to EOF, convert valid lines, close

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Read Limit, then three product codes and integer quantities. Define TYPE Product and store an array of records. Output codes whose quantity is BELOW Limit, in input order; if none, output none.

// Plan, then write your solution

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Explain your reasoning

Explain your choice of data structure and loop. Identify one boundary case and predict its result. For a subroutine, explain what is returned or changed in the caller.

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Review your explanation against these criteria