EDEXCEL GCSE CS Summary

What is decomposition in programming?

• Breaking down problems into smaller parts

• Combining different algorithms

• Writing complex code

• Using high-level languages

Answer explanation

Decomposition in programming refers to breaking down complex problems into smaller, manageable parts. This approach simplifies problem-solving and enhances code organization, making it easier to understand and maintain.

What does abstraction mean in computer science?

• Hiding complex details

• Writing detailed code

• Increasing programme size

• Using low-level languages

Answer explanation

In computer science, abstraction refers to the concept of hiding complex details to simplify interactions and enhance usability. This allows programmers to focus on high-level operations without needing to understand the intricate workings beneath.

Which of the following is a benefit of using subprogrammes?

• Reducing code redundancy

• Increasing code size

• Complicating the code

• Making the programme slower

Answer explanation

Using subprogrammes helps in reducing code redundancy by allowing code to be reused across different parts of a program. This leads to cleaner, more maintainable code, unlike the other options which suggest negative impacts.

What is an algorithm?

• A detailed code implementation

• A set of instructions to solve a problem

• A programming language

• A type of data structure

Answer explanation

An algorithm is defined as a set of instructions to solve a problem. It outlines the steps needed to achieve a specific goal, unlike a detailed code implementation, programming language, or data structure.

Which structure is used for decision-making in algorithms?

• Sequence

• Selection

• Repetition

• Iteration

Answer explanation

The correct choice is Selection, as it is the structure used for decision-making in algorithms. It allows the algorithm to choose different paths based on conditions, unlike Sequence or Repetition, which do not involve decision-making.

What type of loop executes code a specific number of times?

• Count-controlled loop

• Condition-controlled loop

• Infinite loop

• Nested loop

Answer explanation

A count-controlled loop executes a block of code a specific number of times, based on a predetermined count. This distinguishes it from condition-controlled loops, which run based on conditions, and infinite loops, which never terminate.

What is a key feature of a while loop?

• Executes a block of code at least once

• Executes code while a condition is true

• Executes code a specific number of times

• Always ends in an error

Answer explanation

A while loop executes code as long as a specified condition is true. This means it can run multiple times or not at all, depending on the condition, making 'Executes code while a condition is true' the correct choice.

In pseudocode, how would you denote a variable?

• LET

• SET

• VARIABLE

• DEFINE

Answer explanation

In pseudocode, the keyword 'SET' is commonly used to denote a variable assignment. While 'LET', 'VARIABLE', and 'DEFINE' may be used in some contexts, 'SET' is the most widely recognized choice for this purpose.

Which of the following is an arithmetic operator?

• AND

• OR

• NOT

• *

Answer explanation

The correct answer is '*' because it is an arithmetic operator used for multiplication. The other options (AND, OR, NOT) are logical operators, not arithmetic.

What is the purpose of a trace table?

• To document code

• To track variable changes

• To define data types

• To optimise code

Answer explanation

A trace table is used to track variable changes throughout the execution of a program. It helps in understanding how data evolves step by step, making it easier to debug and verify the logic of the code.