Topic 2.1: Elements of Computational Thinking

Question 1

What are Preconditions

Answer 1

• Things which are needed before the program can run.
• The code expects the information passed to it to meet certain criteria.
• The code may test for these when it is run.
• They may instead be included within documentation.
• Including this information within documentation reduces the complexity of the program and makes it easier to use.
• Preconditions make it easier to reuse subroutines.

Question 2

What is Abstraction

Answer 2

• Removing unnecessary detail.
• Representing the key elements of the problem.

Question 3

Decisions affecting problem flow

Answer 3

• There may be many routes through a program.
• Decisions by the user will affect the route taken.
• It is important to identify places where the user will need to make a decision and plan for the decisions they may make.

Question 4

What is Procedural Abstraction

Answer 4

• Allows a programmer to use a function without understanding the detail of its implementation.
• Used with data structures and in decomposition.
• Models the purpose of a subroutine without considering how it does what it does.

Question 5

What is Abstraction by Generalisation

Answer 5

• Similar elements of a problem may be grouped together.
• This allows common problems to be categorised.
• They can then be solved with a common solution.

Question 6

Benefits of Reusable program components

Answer 6

• Make development less time consuming
• Makes development cheaper