Software Design & Development

Question 1

The software development process is described as being ‘iterative’, what does this mean?

Answer 1

The process being ‘iterative’ means that you may go back to a certain stage at any point in the process.

Question 2

What takes place in the ‘Analysis’ stage of the software development process?

Answer 2

In the analysis stage, the functional requirements of a programme are established based off of the client’s needs.

Question 3

What are ‘functional requirements’ in a programme?

Answer 3

The ‘functional requirements’ of a programme are the functionalities a program must be able to perform in order to be fit for it’s purpose.

Question 4

What are the three stages we can split the ‘functional requirements’ of a programme into?

Answer 4

The three stages we can split the ‘functional requirements’ of a programme into are the inputs, the processes, and the outputs.

Question 5

What are ‘inputs’ in computer programmes?

Answer 5

In computer programmes, an ‘input’ is the data received by a programme, often by a user in the form of a prompt, log-in screen, and etc.

Question 6

What are ‘processes’ in computer programmes?

Answer 6

In computer programmes, the ‘process’ is the part of the programme where the data derived from the input is used to generate an output.

This can be through the form of concatenation, accessing a database, and etc.

Question 7

What is an ‘output’ in computer programmes?

Answer 7

The ‘output’ is how the computer presents the results of the process, this is often done by displaying the processed data on the user interface..

Question 8

What takes place in the ‘design’ stage of the software development process?

Answer 8

In the ‘design’ stage, the functional requirements of a programme are iterated upon, and key data types and structure which will be used in the code are identified.

This stage allows for far easier implementation, as the design notations used are based off of universal programming constructs.

Question 9

What are the three different types of design notations?

Answer 9

The three types of design notations are structure diagrams, flowcharts, and pseudocode.

Question 10

What is a ‘structure diagram’?

Answer 10

A ‘structure diagram’ is a visual design notation.

It uses a small variety of symbols to show what is being done at any point of a programme.

‘structure diagrams’ are read from the left hand side, to the right.

Question 11

What is a ‘flowchart’?

Answer 11

A ‘flowchart’ is a visual design notation.

‘Flowcharts’ use a wide variety of symbols to show what is being done at any point in a programme.

‘Flowcharts’ are read in the direction at which they flow.

Question 12

What is ‘pseudocode’?

Answer 12

‘Pseudocode’ is a written design notation.

It is unformalized, which means that it is not based on any programming language, and does not follow any set standards.

‘Pseudocode’ is written in a basic code format allowing programmers to clearly state the use of programming constructs.

It is advised you learn this technique for use in questions, as it is by far the simplest to write.

Question 13

How would you design a user interface in the ‘design’ stage?

Answer 13

A wireframe (based on the inputs and outputs) can be constructed, which shows the design of the user interface.

Question 14

What takes place in the ‘Implementation’ stage of the software development process?

Answer 14

In the ‘implementation’ stage, the programme is written in a programming language, and the code written is derived off of the design.

Question 15

What are the three different types of standard algorithms?

Answer 15

The three different types of standard algorithms taught at national 5 are: input validation, running totals within a loop, traversing an array.

Question 16

What is ‘input validation’?

Answer 16

‘Input validation’ is code which checks whether an input is valid and can be used within the programme.

E.g. When a user is asked to input a number, and a string is entered, the user is asked to re-enter the number.

Question 17

What is a ‘running total within a loop’?

Answer 17

A ‘running total within a loop’ is code which iterates on a total every time a loop runs.

E.g. An array of scores is traversed through a loop, and for every index of the array, the score is added onto the total score.

Question 18

What is ‘traversing an array’?

Answer 18

‘Traversing an array’ is code which accesses each item stored in an array, so that the data can be checked or used as part of a process.

E.g. Adding each number within an array, by using a fixed loop, and using the loop counter as the index of the array.

Question 19

What are the 4 ways a programmer can make their code more easily understandable by other programmers?

Answer 19

A programme can be made more easily understandable through 4 key principles:

Using internal commentary to describe the meaning of code,
Using meaningful variable names,
Indenting code,
Adding white-space between different parts of code.

Question 20

What is the ‘testing’ stage of the software development process?

Answer 20

The ‘testing’ stage is where the code written is tested through a wide variety of data to ensure that it is robust.

Question 21

When a programme is said to be ‘robust’, what does this mean?

Answer 21

A ‘robust’ programme is one which will hold up, no matter what input it receives.

Question 22

What are the ways we can ensure a programme is robust?

Answer 22

There are a few ways we can ensure a programme is robust: Implementing extremes, and using exceptional data.

Question 23

What are ‘extreme’ data sets?

Answer 23

‘extremes’ are the lowest and highest values a programme should be able to accept.

Question 24

What are ‘normal’ data sets?

Answer 24

‘normal’ data sets are the expected data sets to be inputted into a programme.

Question 25

What are ‘exceptional’ data sets?

Answer 25

‘exceptional’ data sets are ones which should not be accepted in the programme.

Question 26

What are the three types of errors you can come across in a programme?

Answer 26

The three types of errors you can come across in a programme are: syntax errors, execution errors, and logic errors.

Question 27

What is a ‘syntax’ error?

Answer 27

A ‘syntax’ error is one which occurs when your written code breaks a rule of the programming language.

These are most commonly seen when code is wrongly written, with wrong keywords.

A ‘syntax’ error will cause a crash.

Question 28

What is an ‘execution’ error?

Answer 28

An ‘execution’ error is one that occurs while the programme is running, meaning it will not be highlighted to the programmer as the programme is being written.

This type of error usually occurs when input from a user breaks the rules of a programme, e.g. a user tries to divide a value by 0.

An ‘execution’ error will cause a crash.

Question 29

What is a ‘logic’ error?

Answer 29

A logic error is one which occurs when a program operates unexpectedly.

This is not truly an ‘error’ as it is not caught by the language itself, but it is one which breaks the requirements of a programme.

E.g. when calculating a price, the output price is shown but it is an unexpected value.

It is up to testing the code to find these errors.

Question 30

What are the three predefined functions you should know?

Answer 30

The three predefined functions taught at national 5 are: random, round, length.