Array Index

An array index is the number used to access an Array of Variables created using the Dim command.

Description:

The following examples illustrate the use of array elements.

If we have an array myArray with elements of 1 to 10, filled with random data:

Index        Data
1              5
2              2
3              6
4              5
5              9
6              1
7              0
8              4
9              5
10             7

One can access each piece of data separately by pointing to the Index of the array element:

Print myArray(5)

Printing the data contained in the fifth element of myArray results in an output of:

To change the contents of an array, use it like any other Variable:

myArray(3) = 0

To print the contents of myArray(3), use the command:

Print myArray(3)

Which results in an output of:

Array elements can be indexed using another Variable. In this example we set all elements in our array to zero:

Dim a As Integer
For a = 1 To 10
myArray(a) = 0
Next a

To change a random array element to a random value:

Dim Index As Integer
Dim Value As Integer
index = Int(Rnd(1) * 10) + 1 'This line will simply return a random value between 1 and 10
Value = Int(Rnd(1) * 10) + 1 'This line will do the same
myArray(index) = Value

Examples:

Declare Sub PrintArray()

Dim Numbers(1 To 10) As Integer
Dim Shared OtherNumbers(1 To 10) As Integer
Dim a As Integer

Numbers(1) = 1
Numbers(2) = 2
OtherNumbers(1) = 3
OtherNumbers(2) = 4

PrintArray ()

For a = 1 To 10
Print Numbers(a)
Next a

Print OtherNumbers(1)
Print OtherNumbers(2)
Print OtherNumbers(3)
Print OtherNumbers(4)
Print OtherNumbers(5)
Print OtherNumbers(6)
Print OtherNumbers(7)
Print OtherNumbers(8)
Print OtherNumbers(9)
Print OtherNumbers(10)

Sub PrintArray ()
Dim a As Integer
For a = 1 To 10
Print otherNumbers(a)
Next a
End Sub

See also:

Back to Programmer's Guide

Array Index - FreeBASIC Wiki Manual | FBWiki

Array Index