Embedded Files
Once the problem and functional requirements are understood, the next step is to design the solution.
Why is Design Important?
Without a clear plan, coding a program is like building a house without blueprints—things will break, and fixing errors later will be a nightmare.
A good software design helps:
✔ Plan ahead before coding.
✔ Catch mistakes early.
✔ Make the program efficient and easy to understand.
Data Types & Structures
Data Types & Structures
Before writing code, we need to decide how to store and organize data.
💡 Choosing the right data type makes a program more efficient and prevents errors.
Design Techniques
Design Techniques
To plan the logic of a program, we can use three common design methods:
Structure Diagrams
Structure Diagrams
Structure diagrams break a problem into smaller, manageable steps.
Think of them as a family tree, showing how tasks connect.
Structure diagrams graphically show the steps needed to solve a problem.
Structure diagrams must be read from the top down from left to right
Structure Diagram Symbols:
Process - Used to show that a process is needed.
Loop - Used to show that repetition / iteration is taking place.
Selection - Used to show that there are different outcomes through conditional statements.
Pre-defined function - Used to make use of a pre-defined function (Round, Len, Random)
Example: This diagram represents a program that:
inputs 10 numbers
validates each number (0 to 100)
keeps a running total of the numbers
outputs the final total
Pseudocode
Pseudocode
Pseudocode is structured plain English that describes what a program will do.
The SQA have their own Reference Language which follows these rules:
Example: Finding the Largest of Two Numbers
✔ Readable for both programmers and non-programmers.
✔ Easier to convert into actual code later.
Example
BEGIN
// Receive two numbers from the user
SEND "Enter first number: " TO DISPLAY
RECEIVE num1 FROM INTEGER
SEND "Enter second number: " TO DISPLAY
RECEIVE num2 FROM INTEGER
// Compare numbers and determine the largest
IF num1 > num2 THEN
SEND "The largest number is " & num1 TO DISPLAY
ELSE
SEND "The largest number is " & num2 TO DISPLAY
END IF
END
Flowcharts
Flowcharts
Flowcharts show the flow of decisions using symbols.
Flow Line - Shows the direction of flow within your program
Terminal - Shows the start and end of a problem
Initialisation - Declares variables and arrays or assigns a value
Input / Output - Show data input or data output
Decision - Shows that a decision is to be made, with branches for different outcomes. Used in loops or IF statements.
Process - Used to show that a process is needed.
Pre-defined function - Used to make use of a pre-defined function (Round, Len, Random)
On-page Connector - Used if the flowchart has reached the bottom of a page. The connector lets the chart continue from another point.
Example
The program adds up three numbers entered by the user, and stores the answer in the variable total.
UI Design
UI Design
A program’s user interface (UI) is how users interact with it.
A wireframe is a simple sketch showing:
✔ Where buttons and text fields go.
✔ How information is displayed.
✔ What inputs are required.
Example
Use a wireframe to design the user-interface of a program which:
asks the user to enter three numbers
adds the numbers together
displays the total of the three number
Bringing it All Together
Bringing it All Together
A fully designed program should have:
✅ Well-chosen data types (efficient storage).
✅ A clear structure using diagrams, flowcharts, or pseudocode.
✅ A well-thought-out user interface (wireframes).
Design first, code later. This makes development faster, smoother, and less error-prone.
Google Sites
Report abuse