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ScotlandComputer Science

Software design and development

8 dot points across 8 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do developers work out exactly what a program must do before writing it?

Analysis: identifying the purpose, scope and boundaries of a problem and writing functional requirements in terms of inputs, processes and outputs.
An SQA National 5 Computing Science answer on the analysis stage of software development, covering how to identify the purpose, scope and boundaries of a problem and how to write functional requirements in terms of the inputs, processes and outputs a finished program must provide.
9 min answer →

What building blocks do we combine in a high-level language to make a program work?

Computational constructs: assignment, arithmetic, comparison and logical operators, concatenation, predefined functions, and the control structures of selection and iteration (fixed and conditional).
An SQA National 5 Computing Science answer on computational constructs, covering assignment, arithmetic, comparison and logical operators, string concatenation, predefined functions, and the control structures of selection (IF) and iteration (fixed and conditional loops) used to build programs in a high-level language.
11 min answer →

What data types and data structures does a National 5 program use, and when is each one chosen?

Data types and structures: variables holding character, string, numeric (integer and real) and Boolean values, and the 1-D array as a structure for holding many values of the same type under one name.
An SQA National 5 Computing Science answer on data types and structures, covering the variable types of character, string, integer, real and Boolean, when each is chosen, and how a one-dimensional array stores many values of the same type under a single name accessed by an index.
10 min answer →

How do developers plan a program and its user interface before coding?

Design techniques: representing a program design with structure diagrams, flowcharts and pseudocode, and designing the user interface with a wireframe.
An SQA National 5 Computing Science answer on design techniques, covering how developers plan a program using structure diagrams, flowcharts and pseudocode, how to read and write each notation, and how a wireframe is used to design the layout of a user interface before coding begins.
10 min answer →

What are the stages of the software development process and what happens at each one?

The iterative software development process: analysis, design, implementation, testing, documentation and evaluation, and why the process is iterative rather than strictly linear.
An SQA National 5 Computing Science answer on the software development process, covering the six stages of analysis, design, implementation, testing, documentation and evaluation, what is produced at each stage, and why the process is iterative so that developers loop back to earlier stages when problems are found.
9 min answer →

How are numbers, text and graphics stored using only binary digits?

Low-level operations and data representation: representing positive integers in binary, characters using a code such as ASCII, real numbers using floating point (mantissa and exponent), and graphics as bit-mapped or vector data.
An SQA National 5 Computing Science answer on low-level operations and data representation, covering how positive integers are stored in binary, how characters are stored using a code such as ASCII, how real numbers are stored using floating point with a mantissa and exponent, and how graphics are stored as bit-mapped or vector data.
11 min answer →

What standard algorithms must a National 5 programmer know how to design and code?

Standard algorithms: input validation, running total within a loop, and traversing a 1-D array, each as a reusable pattern built from selection and iteration.
An SQA National 5 Computing Science answer on the three standard algorithms, covering input validation with a conditional loop, keeping a running total inside a loop, and traversing a one-dimensional array with a fixed loop, with worked code-style examples of each reusable pattern.
10 min answer →

How do we test a program and judge whether it is any good?

Testing with normal, extreme and exceptional test data; the three kinds of error (syntax, execution and logic); and evaluating software for fitness for purpose, efficiency, robustness and readability.
An SQA National 5 Computing Science answer on testing and evaluation, covering the three categories of test data (normal, extreme and exceptional), the three kinds of error (syntax, execution and logic), and the four criteria for evaluating software: fitness for purpose, efficiency, robustness and readability.
10 min answer →