Software design and development
Development methodologies
6 phases of the software design process
Phase | Explanation |
Analysis | identify what the program is meant to do when given a problem |
Design | set out the functionality and interface of the program by using pseudocode, flowcharts, structure diagrams, wireframe |
Implementation | write out the code/program |
Testing | check that the program does not have errors/bugs and works as expected |
Documentation | gather the documents produced from each stage of the development process |
Evaluation- | check if the program is fit for purpose, efficient, robust and readable |
The software development phase is iterative because you can revisit and edit any one of the stages
Analysis
The functional requirements of a program are the inputs, processes and outputs.
Input- data entered into the computer
Processes- what does the computer do with the information
Output- the result of the process being returned to the user. It can be displayed to a screen, sent to a printer, played through speakers as audio.
For example:
A program asks the user to enter length of one side of a square. The program should then calculate and display the area of the square.
Input- length of one side
Processes- calculating the area
Output- area of square
Design
Data type | Example |
Character (not often used) | ‘a’ , ‘b’ |
String (words) | “hello” |
Integer (whole numbers) | ‘1’ ‘21’ |
Float/Real (decimal numbers) | ‘1.2’ ‘23.6’ |
Boolean (yes/no) | True/False |
The only data structure you can be asked is a 1-D Array.
Example: [‘hello’,’world’] is one 1-D array of type string.
Flowcharts
A flowchart is a graphic way of designing the steps of the program. They use symbols and short descriptions to represent each step.
Structure diagrams
A structure diagram is a graphic way of showing the steps needed for the program.
They are read top-left-right-bottom.
Pseudocode
Pseudocode is a way of designing the steps of a program using phrases similar to program code lines.
Example:
A program is required to repeatedly display 'Hello World' until the user enters 'stop'. Use pseudocode to design this program.
