AS Computing
Unit 1.5 Data Structures
What is a data structure?
A data structure is a collection of data items stored in memory, in addition a number of operations
are provided by the software to manipulate that data structure.
So, why do we use them?
Take the code block shown here:
The problem with this piece of code is
that the program will only store the last
name and mark entered. This is
because each name and mark is stored
in the same variable and every time a
new piece of data is entered the old
one is overwritten.
To perform this task properly we would
use a one-dimensional array.
So, instead of setting up 5 separate variables we can create one array to hold all of the data entered.
So you would have an index with 5 elements and each array element would refer to the respective
piece of data. Array element numbers start at 0, so, the first piece of data in the array could be
retrieved by: array (0).
One Dimensional Arrays
The arrays so far have been called one dimensional because they can be represented as linked cells
stretched out in a one dimensional line in the following ways:
Array(0) Array(1) Array(2) Array(3) Array(4)
Or like this:
Index 0 1 2 3 4
Stored Value
Page |1 Luca Passariello AS Computing
Unit 1.5 Data Structures
What is a data structure?
A data structure is a collection of data items stored in memory, in addition a number of operations
are provided by the software to manipulate that data structure.
So, why do we use them?
Take the code block shown here:
The problem with this piece of code is
that the program will only store the last
name and mark entered. This is
because each name and mark is stored
in the same variable and every time a
new piece of data is entered the old
one is overwritten.
To perform this task properly we would
use a one-dimensional array.
So, instead of setting up 5 separate variables we can create one array to hold all of the data entered.
So you would have an index with 5 elements and each array element would refer to the respective
piece of data. Array element numbers start at 0, so, the first piece of data in the array could be
retrieved by: array (0).
One Dimensional Arrays
The arrays so far have been called one dimensional because they can be represented as linked cells
stretched out in a one dimensional line in the following ways:
Array(0) Array(1) Array(2) Array(3) Array(4)
Or like this:
Index 0 1 2 3 4
Stored Value
Page |1 Luca Passariello AS Computing
