The document discusses input validation techniques to ensure users enter acceptable data values. It provides examples of acceptable data ranges for common data types like age, sex, lottery numbers, and school year/tutor groups. It also discusses validating more complex entries like bank account numbers and names. The basic input validation pseudocode asks the user to re-enter data until it is within the defined acceptable range.

1. Input Validation

2. Input Validation
Ensure that the data which the user has entered is within a
reasonable range
Program should repeatedly ask the user to re-enter until acceptable
data has been entered
Example:
A program ask the user to enter a month of the year in numeric
form
Acceptable data entries are 1,2,3,4,5,6,7,8,8,10,11,12
If the user enters any other data they should be asked to re-enter

3. Input Validation

4. Input Validation
What are the acceptable data ranges for the following:
Input Valid Entries
Day of the week in numeric form
A person’s age
A person’s sex
A lottery number
A pupil’s year group
A pupil’s tutor group

5. Input Validation
What are the acceptable data ranges for the following:
Input Valid Entries
Day of the week in numeric form 1 – 7
A person’s age 0 – 115
A person’s sex m, f, male, female
A lottery number 1 – 49
A pupil’s year group 1 – 6
A pupil’s tutor group Various solutions…

6. Input Validation
Input validation works well with simple numeric data, but what
about more complex entries?
Bank account number – program could check the correct
number of digits, and that all characters are numeric
Person’s name – program could ask the user if the entry is
correct (Y/N)
Where possible, programs can reduce errors by restricting
options using drop-down menu. But will this still be correct?

7. Pseudocode
The basic input validation pseudocode takes the following
form

8. Pseudocode – Exam Score
A program should ask the user to enter their exam score
Acceptable scores are 0-100

9. Code – Exam Score
A program should ask the user to enter their exam score
Acceptable scores are 0-100

10. Pseudocode – Multiple choice
A program should ask the user to enter the answer to a
multiple choice question: 1, 2 or 3

11. Pseudocode – Multiple choice
A program should ask the user to enter the answer to a
multiple choice question: 1, 2 or 3

12. Code – Multiple Choice
A program should ask the user to enter the answer to a
multiple choice question: 1, 2 or 3