A 1D array is a data structure that can be thought of like a list. For example if you were asked to create a program that stores five names you might think that you could use 5 variables, what about a program that stores 20 or even 1000?
To create an array we use the DIM command but we add in a new piece of information.
DIM Number(5) as Integer
We use Arrays to store lists of similar items, like class names or class marks. The allows us to reference all the items with the same name and therefore simplify coding by using loops.
Visual basic uses the DIM command to set up an array.
DIM StrName(5) as String ‘ creates a Array with 6 elements of type string Continue reading Arrays
Jonathan asked me a couple of very good questions today and I thought I would share my answers.
What is the difference between a linear CCD and a Array CCD?
Is it just CCDs that are used in digital cameras.
What does WRL stand for
So with all this on the blog I updated the Multimedia Glossary, after all what else did I have to do.
I didn’t know that Visual Basic Express Edition could handle a string as an Array. Some programming languages require you to use individual characters and then create an array of these to create a string, so I guess that is what is going on. I also found this article on spiting and joining arrays.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ClickDim UserString As StringGetstring(UserString)DisplayString(UserString)End Sub
Private Sub GetString(ByRef UserString As String)UserString = InputBox(“What is your name”)End Sub
Private Sub DisplayString(ByVal UserString As String)For Counter = 0 To (Len(UserString) – 1)ListBox1.Items.Add(UserString(Counter))NextEnd Sub
Below is the program from today’s lesson. It is not completed, I would like you to Change the program to display the average with two decimal places. Please add your solution with a comment below.
Private Sub CmdStart_Click()
'load an Array with data from a list box
'list box is hidden on the form
'List Boxes count from 0 so add a heading to the fist item
Dim IntNumber(20) As Integer
Dim StrName(20) As String
Dim intavg As Integer
Call Load_Array(IntNumber(), StrName())
Call Calc_Average(IntNumber(), intavg)
Call Display_Array(IntNumber(), StrName(), intavg)
End Sub
Private Sub Load_Array(ByRef Number() As Integer, ByRef StrName() As String)
Dim Counter As Integer 'local Variable
For Counter = 1 To 20
Number(Counter) = LstNumbers.List(Counter)
StrName(Counter) = LstNames.List(Counter)
Next
End Sub
Private Sub Calc_Average(ByRef IntNumber() As Integer, ByRef intavg As Integer)
Dim IntSum As Integer
For Counter = 1 To 20
IntSum = IntSum + IntNumber(Counter)
Next
intavg = IntSum / 20
End Sub
Private Sub Display_Array(ByRef Number() As Integer, ByRef StrName() As String, ByVal intavg)
'Standard procedure as used in previous programs
Dim Counter As Integer 'local Variable
For Counter = 1 To 20
Form1.Print StrName(Counter) & " scored " & Number(Counter) & "%"
Next
Form1.Print "Average = " & intavg & "%"
End Sub
Today’s lesson introduced 1-D arrays. The class started off by creating 3 programs.
1. Create a program to take in 3 numbers and display the sum and average.
2. modify the program to work with 5 numbers.
3. Modify the program to display the numbers after it displays the sum and average.
The class were given the main steps and asked to refine it, before starting the task. Each task was to be saved in separate folders.
The class was then asked to modify the program for 100 numbers. This led to discussion about the need for a new data type that could store a list of values, this data type is called Array.
Scratch was used to show how arrays can be used. The class then looked at the DIM command’s help page to discover how to set up an Array.
DIM IntNumber(50) as Integer
Where (50) is the number of items in the array.
The program was modified to allow entry of 100 values before the period finished.
HOMEWORK
Write the refinements for the main program given for 100 numbers.
