Computational Thinking

Question 1

What is abstraction?

Answer 1

Process of removing unnecessary detail and focusing on the important features of a problem so that it becomes easier to understand and solve.

Question 2

Why is abstraction used in computer science?

Answer 2

• Reduces complexity
• Makes problems easier to solve
• Allows systems to be understood at different levesl

Question 3

What is representational abstraction?

Answer 3

Removes excess detail to create a simplified model of a problem that only includes key features.

Question 4

What is abstraction by generalisation?

Answer 4

Identifying common patterns between problems so that one general solution can solve multiple similar problems.

Question 5

What is data abstraction?

Answer 5

Hdes the internal representation of data and only exposes the operations that can be performed on it.

Question 6

What are abstraction layers?

Answer 6

Divide a system into levels where each layer hides the complexity of the layer below it.

Question 7

Give examples of abstraction layers.

Answer 7

Examples include programming languages (high-level language to machine code) and networking models such as TCP/IP layers.

Question 8

Give advantages of abstraction.

Answer 8

Reduces program complexity, allows focus on key features, improves system design, and makes programs easier to maintain.

Question 9

What is thinking ahead in program design?

Answer 9

Thinking ahead involves considering inputs, outputs, constraints, and possible errors before writing an algorithm.

Question 10

What are inputs?

Answer 10

Inputs are data provided to a system that are required for processing, such as keyboard input, sensor data, or file data.

Question 11

What are outputs?

Answer 11

Outputs are results produced by a program after processing input data, such as displayed results or printed reports.

Question 12

What must programmers consider about inputs and outputs?

Answer 12

Input method, output method, data types used, and data structures used.

Question 13

What is a precondition?

Answer 13

A precondition is a condition that must be true before a program or function can run correctly.

Question 14

Give an example of a precondition.

Answer 14

Before popping from a stack the stack must not be empty; before pushing the stack must not be full.

Question 15

Why are preconditions useful?

Answer 15

They simplify program design, reduce debugging, improve reliability, and make subroutines reusable.

Question 16

What are reusable components?

Answer 16

Reusable components are program modules that can be used in multiple programs without modification.

Question 17

Give examples of reusable components.

Answer 17

Functions, procedures, classes, and abstract data types.

Question 18

Give advantages of reusable components.

Answer 18

Already tested so more reliable, reduces development time, reduces cost, and improves productivity.

Question 19

What is procedural thinking?

Answer 19

Procedural thinking involves breaking a problem into ordered steps that can be executed sequentially.

Question 20

What is problem decomposition?

Answer 20

Problem decomposition is breaking a complex problem into smaller manageable sub-problems.

Question 21

Why is problem decomposition useful?

Answer 21

It simplifies complex problems, allows tasks to be divided among programmers, improves debugging, and improves organisation.

Question 22

What is top-down design?

Answer 22

Top-down design starts with the overall problem and repeatedly breaks it into smaller sub-problems.

Question 23

What is another name for top-down design?

Answer 23

Stepwise refinement.

Question 24

What is stepwise refinement?

Answer 24

Progressively breaking a problem into smaller steps until each step can be implemented as a single task or subroutine.

Question 25

What is a subroutine?

Answer 25

A self-contained section of code that performs a specific task.

Question 26

What are advantages of subroutines?

Answer 26

Reusable, easier debugging, improved readability, and supports modular programming.

Question 27

What must programmers consider when combining subroutines?

Answer 27

The order of execution, the data passed between modules, and how modules interact.

Question 28

What is modular programming?

Answer 28

Designing software using separate modules that each perform a specific task.

Question 29

Advantages of modular programming?

Answer 29

Easier maintenance, easier debugging, reusable modules, and supports teamwork.

Question 30

How do modules communicate?

Answer 30

Modules communicate through parameters and return values passed between subroutines.

Question 31

Why must programmers anticipate errors when thinking ahead?

Answer 31

To handle invalid input, boundary cases, or unexpected situations and ensure the program runs reliably.