Defensive Programming and Testing (yr 11)

Question 1

What is defensive programming?

Answer 1

Defensive programming is a practice of writing code that anticipates and handles misuse, errors, and unexpected inputs to make programs more reliable and secure.

Question 2

Name three defensive design techniques.

Answer 2

1. Input Validation: Ensures inputs are in the expected format.
2. Authentication: Verifies user identity (e.g. login systems).
3. Maintainable Code: Using comments, indentation, and meaningful variable names to improve readability.

Question 3

What is iterative testing?

Answer 3

Testing carried out during development to ensure each part of the program works as it is built.

Question 4

What is final/terminal testing?

Answer 4

Testing performed once development is complete to check the whole system meets requirements.

Question 5

What is a trace table?

Answer 5

A table used to manually track the values of variables and outputs at each step in an algorithm to detect logic errors.

Question 6

What is the difference between normal, boundary, and erroneous data?

Answer 6

• Normal data: Inputs that are expected and valid.
• Boundary data: Values at the edge of acceptable ranges.
• Erroneous data: Invalid inputs used to test error handling.