IB CS Review 4 - 25/26

Which of the following is NOT one of the four pillars of computational thinking?

• Abstraction
• Decomposition
• Compilation
• Pattern recognition

Answer explanation

The four pillars are abstraction, decomposition, pattern recognition, and algorithmic thinking.

What does decomposition mean in computational thinking?

• Removing errors from code
• Breaking a complex problem into smaller parts
• Hiding details
• Optimising an algorithm

Answer explanation

Decomposition involves breaking problems into smaller, manageable parts.

Abstraction in computational thinking refers to:

• Focusing on important details and ignoring irrelevant ones
• Writing pseudocode
• Translating algorithms into code
• Debugging errors

Answer explanation

Abstraction is about ignoring unnecessary details and focusing on essentials.

Pattern recognition is useful because:

• It helps create bugs
• It allows us to identify similarities that can simplify solutions
• It prevents abstraction
• It ensures the code runs faster

Answer explanation

Pattern recognition identifies similarities that help simplify solutions.

Which of these best describes an algorithm?

• A programming language
• A step-by-step set of instructions to solve a problem
• A debugging tool
• A design diagram

Answer explanation

An algorithm is a step-by-step procedure for solving problems.

What is pseudocode mainly used for?

• Outlining an algorithm without syntax rules
• Writing executable code
• Translating machine language
• Debugging programs

Answer explanation

Pseudocode is a human-readable outline of an algorithm.

Which diagram shows the sequence of steps in an algorithm?

• ER diagram
• Flowchart
• Class diagram
• UML diagram

Answer explanation

Flowcharts are diagrams that show steps in an algorithm.

What does the term 'trace table' mean?

• A table used to track variable values during algorithm execution
• A table of programming errors
• A database record
• A table for storing pseudocode

Answer explanation

Trace tables track variable values at each step of execution.

What is meant by 'iteration' in programming?

• Repeating a set of instructions
• Choosing between options
• Declaring a variable
• Defining an algorithm

Answer explanation

Iteration means repeating steps using loops.

In programming, a variable is:

• A fixed value
• A named storage location in memory
• A debugging tool
• A type of algorithm

Answer explanation

Variables are named memory locations that store data.