4.2.1.3 Reading and writing text and binary files Quiz: AQA Computer Science, Unit 2

The 20 questions

1. What is the difference between a text file and a binary file?

   • A binary file holds only characters, while a text file holds only numbers stored in raw form
   • A text file holds characters that can be read as text, while a binary file holds raw data that is not plain text
   • Text files cannot be read by programs, so they can only be opened and printed by a person directly
   • Binary files can only store strings, so any number must be converted to text before it is saved

2. Which operation is needed to read data from a text file into a program?

   • Convert the file to a binary format
   • Write each item to the file before opening it
   • Open the file for reading, then read each line or item
   • Delete the file first

3. Which operation adds data to the end of an existing text file without deleting what is already there?

   • Open the file in append mode and write
   • Open the file in read mode and write
   • Open the file as binary and read
   • Delete the file and create a new one

4. Why might a program write data to a binary file rather than a text file?

   • Binary files cannot store numbers, so they can only be used to hold characters of text
   • Binary files store data in a compact form that does not need text conversion
   • Binary files can be read by people without any tools, because the data is in plain English
   • Binary files do not need to be opened, because the operating system loads them automatically

5. A text file is read line by line until the end of the file is reached. What is the main purpose of the end-of-file check?

   • To delete the file after reading, so that the same data cannot be read again by the program
   • To convert every line to a number, so that the file contents are ready for arithmetic
   • To open the file for writing, so that new lines can be added after the last line read
   • To stop the loop when there is no more data to read

6. A binary file stores a record with a name and a score. Which statement is correct?

   • Fields can be read back in any order without knowing their types
   • Each field must be read back in the same order and type it was written
   • The name and score must be stored as text
   • Binary files cannot store records

7. What does it mean to write a record to a file?

   • Delete the record from memory, freeing the space it used so that the file can be closed
   • Convert the record into a constant, so its values can never be changed by the program later
   • Print the record on a screen only, so that the user can see its fields but nothing is saved
   • Store all the fields of the record in the file so it can be read back later

8. A program writes a record to a text file as the line Sam,42. Which operation is needed when reading the age back as a number?

   • Boolean conversion of Sam
   • Float to date/time conversion of 42
   • String to integer conversion of the text 42
   • Integer to string conversion of Sam

9. Which description best fits a file used to hold a list of records that can be read sequentially?

   • A file with no records
   • A file where records are accessed only by a hash key
   • A file processed from the first record to the last in order
   • A file that is always randomly accessed

10. What is a potential problem if a program fails to close a file after writing to it?

    • The file becomes a constant, so it can no longer be written to by any program in the future
    • Data may not be saved correctly or the file may be left in an inconsistent state
    • The program runs faster, because the operating system stops checking the file for changes
    • The file is automatically converted to binary, so the text content is lost when the program ends

11. Which check should a program make before reading from a file that the user names?

    • Check that the file exists and can be opened
    • Check that the file is in alphabetical order
    • Check the file's colour
    • Check that the file has exactly 10 lines

12. A program reads a text file of 100 numbers, one per line. Which structure is most suitable to hold them for processing?

    • A binary tree of strings only
    • A single Boolean
    • An array of 100 integers
    • A single constant

13. A file contains records of students in a fixed order. Which access method reads one record after another?

    • Parallel access by pointer
    • Direct access by hash
    • Sequential access
    • Random access by key

14. Why must a text file be opened in the correct mode before it is used?

    • Reading and writing require different modes, and using the wrong one causes an error
    • The mode decides the file's name, so the program must choose a mode before naming the file
    • The mode changes the colour of the text on screen, so that reading and writing show different colours
    • Modes are only needed for binary files, since text files can always be read and written freely

15. A binary file of records is written with the name field before the score field. What must happen when it is read?

    • The name is read first, then the score, in the same order
    • Only the name is read and the score is ignored
    • The score is read first, then the name, to save time
    • The file cannot be read back at all

16. What is the main reason to use a file rather than only variables in memory?

    • Data is kept after the program ends and can be used again later
    • Files reduce the need for any data types
    • Files stop the program from crashing
    • Variables in memory are always slower to use than files

17. A program writes a line of text to a file, then reads the file expecting to see that line but gets nothing. What is a likely cause?

    • Text files cannot contain lines, so each line written is discarded when the file is saved
    • The file was not closed or flushed before reading back
    • The program used the constant keyword, which stops the file from being read until it is closed
    • The program was run too quickly, so the file had not yet been created when it was read back

18. Which statement best describes a field in a record that is stored in a file?

    • A single named item of data within the record, such as a name or score
    • A whole file on a disk, which holds many records that are stored one after another in order
    • A pointer to another file, which gives the location of the record's data on the disk
    • A stack frame for one subroutine, which holds the locals and parameters of a single call

19. A program must update one record in a large binary file without rewriting the rest. Which access method helps?

    • Random access to the record's position
    • Only sequential reading from the start
    • Deleting the whole file first
    • Converting the file to text

20. Which is a suitable use of a binary file?

    • Storing an image's raw pixel data
    • Storing a list of names for a printed report
    • Storing a note that a person needs to read
    • Storing a sentence in a letter

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