1. 4d – Program Design Lingma Acheson CSCI N331 VB .NET Programming
Department of Computer and Information Science, IUPUI

2. Pseudocode
Half English, half programming language to aid in program design
E.g. If the score is greater than 90Then
letter grade is A
End IF
Translated to real code:
If intScore > 90 Then
strGrade = “A”

3. Problem Solving Phase one – understand the problem
Read and study the requirements
Phase two – program design
Develop a plan
Phase three – program implementation
Translate the design into actual code
Phase four – program testing
Run the program and test with different inputs
Phase five – program documentation
Document technical details, user manuals, etc.

4. Program Design Must have a plan before you start coding!
Think through the whole program without using a computer.
With a plan, coding is simply straightforward translation.
A five step process
Initialization
Input
Processing
Output
Clean up

5. Program Design Calculator example Expand each step if necessary
Initialization: None
Input: 2 numbers and 1 operation
Processing: Take the two inputs and perform the operation
Output: Tell user the result from operation
Clean up: None
Expand each step if necessary
How to take two numbers? Create 2 textboxes.
How to provide operators? buttons, radio buttons, or combo boxes?
Create a submit button and use button event to take the two inputs and perform the operation

6. Program Design Further expand each step if necessary
Output: Tell user the result from operation
Create a label to tell user the result
Clean up: None
Further expand each step if necessary
Input: 2 numbers and 1 operation
Create 2 textboxes.
Create 4 buttons, one for each operation
Processing: Take the two inputs and perform the operation
Create a submit button and use button events to take the two inputs and perform the operation
In each button event
Create three variables of type Double
Take the two inputs, change them into numeric values and store them into variables.
Perform the operation and store them into the result variable.
Change the result back into text and set it as the text of the label

7. Program Design
Use pseudocode to convert the design into half programming code to ease the translation process.
E.g.
Processing: Take the two inputs and perform the operation
Create a submit button and use button events to take the two inputs and perform the operation
In each button event
Create three variables of type Double
Dim dblInput1, dblInput2, dblResult As Integer
Take the two inputs, change them into numeric values and store them into variables.
dblInput1 = Val(the text of textbox1) …
Perform the operation and store them into the result variable.
dblResult = dblInput1 + dblInput2
Design the interface layout

8. Program Implementation
Finally the coding process
Open Visual Studio 2008
Translate the design into actual code