Software Development
Year 10
DESIGN
MOCK - UP
It is important to display all the graphical user interface elements in your diagram. label ALL objects with object type and all objects that handle variables and data with their names. See image below for an incomplete Mock up of a mobile phone app. How many objects have not been labeled?
Also you can include justifications for your designs in relation to Useability, Maintainability, Readability and Validation/Feedback.
OBJECT DESCRIPTION TABLE
From your completed design layout, you can construct a more detailed table of objects. This identifies the object's name, type, method/event and description.
Using the Hungarian notation and Camel Case a text box that reads in the user's name should be called "txtName". This kind of object allows the user to enter text into it's "text" property. This means the object's purpose is "Method". When an object is used to have it's properties changed during execution, it is called a Method. However, when an object's purpose is to react to an event, such a button when the user clicks it, this is called an event object.
DATA DICTIONARY
This design tool is crucial to your planning. Herein we define all the variables we will use in the solution, what names we give them, the data type each variable will handle, the size of the data in bytes, whether it is a global or local variable and a brief description.
Variable names need to be structured in Hungarian Notation and Camel Case in most cases to make the code as easy to read as possible. For example if the user to to enter their Name into a textbox, it would be held in a variable called strName. Str indicates the data type string.
It is important to note the data types. If these have been incorrectly defined you will experience errors in your executable code. For example, if you have are calculating the average of some values, you will not be able to set the variable to integer. If in the calculation of the average the returning value is not an integer the program will not run.
Likewise if you have an array with many types of data they willneed to all be declared as strings. Once a value is access from the array, the data type can be changed within the code.
ALGORITHMS
Algorithims are solutions to logic problems. In software development we use pseudocode to write algorithms. Pseudocode is like computer coding but easier to read and is often completed with english words for clarity.
All pseudocode algorithms must begina dn end with "START" or "BEGIN" and "END"
Algerbraic elements can be used: +, −, ×, /, mod and logical elements such as "and", "or" and "not".
Comparison elements =, ≠, <, >, ≤, ≥, <>.
When allocating data to a variable the symbol ← is used.
Algorithms allow for the outline of control structures used to design the solution.
Decision Control Structures
START
IF Condition is true THEN
Action A
ELSE
Action B
END
START
CASE Selection
CASE 1 : Do Action A
CASE 2 Do Action B
END CASE
END
Iteration Control Structures
Counted Loops
START
FOR counter ← 0 to 9
Actions
NEXT
END
Conditional Loops
(Pre-conditional Loop)
START
Do While Condition is true
Actions
End While
END
(Post- Conditional Loop)
START
Repeat
Actions
Until a Condition is True
END