2.1.3

Question 1

Procedural Abstraction

Answer 1

• 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

Question 2

Problem Decomposition

Answer 2

• Breaking down a large problem into smaller parts.
• These smaller parts are easier to solve.

Question 3

Decomposition in a team

Answer 3

• Top down design, also called stepwise refinement is often used to do this.
• This technique divides a problem into levels of complexity.
• Problems are broken down over and over until each problem is a single task.
• Each task can then be solved with a single subroutine.

Question 4

Subroutines in decomposition

Answer 4

• Subroutines can be tested and developed separately.
• Consider how each subroutine is implemented.
• The subroutines need to be joined to form the whole solution.
• Start with the lowest level components and work up.
• Some tasks may be solved with an existing module or library.

Question 5

The Order of Steps

Answer 5

• It is important to consider the order in which operations are performed.
• Certain inputs may be required before processing.
• Inputs may need to be validated, this must occur after the input is received and before it is processed.
• It may be possible for several subroutines to be executed at the same time.
• Also consider how subroutines interact with one another.
• Code should be written to prevent operations occurring in an order which would cause an error or prevent the program from functioning as intended.