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Unit 1: Algorithms and programming principles

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is computational thinking, and how are algorithms expressed using flowcharts and pseudocode?

Computational thinking through decomposition and abstraction, what an algorithm is, and expressing algorithms using flowcharts and pseudocode.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on computational thinking and algorithms, covering decomposition and abstraction, what an algorithm is, and how algorithms are expressed using flowcharts (with the standard symbols) and pseudocode, with worked examples.
9 min answer →

What are the logic operators AND, OR and NOT, how do truth tables work, and what do logic gates do?

Boolean logic using the AND, OR and NOT operators, constructing truth tables, the logic gates, and simplifying simple logic expressions.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on logical operations, covering Boolean logic with the AND, OR and NOT operators, constructing truth tables, the matching logic gates, and simplifying simple logic expressions, with worked examples.
8 min answer →

What are the three basic programming constructs, and how are variables, constants and operators used?

The three programming constructs (sequence, selection and iteration), the use of variables and constants, and arithmetic, relational and logical operators.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on programming constructs, covering sequence, selection and iteration (including IF statements and FOR and WHILE loops), the difference between variables and constants, and arithmetic, relational and logical operators with worked examples.
9 min answer →

How do the linear search and binary search algorithms work, and when is each suitable?

The linear search and binary search algorithms, how each works, and the conditions under which each is suitable.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on searching algorithms, covering how the linear search and binary search work step by step, the requirement that binary search needs sorted data, and the relative efficiency of the two methods with worked examples.
9 min answer →

How do the bubble sort and merge sort algorithms put data into order, and how do they compare?

The bubble sort and merge sort algorithms, how each puts data into order, and the relative efficiency of the two methods.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on sorting algorithms, covering how the bubble sort works by repeatedly swapping adjacent items, how the merge sort works by splitting and merging, and the relative efficiency of the two methods with worked examples.
9 min answer →

What are subprograms, and why is a modular, structured approach to programming used?

The use of subprograms (procedures and functions) and parameters, and the benefits of a modular, structured approach to programming.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on subprograms and program structure, covering procedures and functions, the use of parameters, the difference between a procedure and a function, and the benefits of a modular, structured approach to writing programs.
8 min answer →