IGCSE Computer Science Paper 2 Definitions Worksheet: 8.2 Arrays and 8.3 File Handling (Modules 479–488)
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Key terms
Write what each term means, in your own words.
1
trace table
2
1D or 2D array
3
common array mistakes
4
DECLARE, FOR INPUT, FOR OUTPUT
5
file
6
"FileA.txt"
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file mode
8
DECLARE LineOfText : STRING
9
OPENFILE "Scores.txt" FOR WRITE
Answer Key
IGCSE Computer Science Paper 2 · Modules 479–488 · Student wording will vary for definitions
1trace table — Tracks Row, Column and the element changed. The outer loop variable stays fixed while the inner one runs through all its values. Total passes = rows x columns.
21D or 2D array — Use a 1D array for a simple list of values. Use a 2D array when data forms a table or grid, so each value needs two indexes: a row and a column.
3common array mistakes — Typical bugs: loop limits not matching ARRAY[l:u], swapped row and column indexes, a total not reset to 0, or the wrong data type stored. Check bounds, index order and starting values.
4DECLARE, FOR INPUT, FOR OUTPUT — The pattern of a complete array program: declare the array, use a FOR loop to INPUT a value into each element, then use a second FOR loop to OUTPUT every element.
5file — A file keeps data on storage so it still exists after the program closes, unlike variables. The program can read it back next time it runs, such as a saved high score or a list of names.
6"FileA.txt" — A file identifier is the name of the file, written as a string in double quotes with its extension, such as "FileA.txt". The same identifier is used in every file command.
7file mode — States what a program will do with an open file: READ gets data out of it, WRITE puts data into it. A file is open in only one mode at a time, chosen by what the program needs.
8DECLARE LineOfText : STRING — Creates a variable named LineOfText that holds text. Declare it before the file commands that use it, for example before READFILE stores a line in it.
9OPENFILE "Scores.txt" FOR WRITE — Opens the file Scores.txt in write mode so data can be written into it with WRITEFILE. The file must be opened before writing. Keywords are in capitals.