Arrays In Java
Definition of Array ?
An Array is a group of related data items that share a common name with same data type. An individual variable in the array is called an array element.
We can define an array name
rollno to represent a set of
rollno of group of students. An index number is present in brackets after the array name.
How to create an Array ?
To create an array, you need to perform three steps:
- i) Declare the array
- ii) Create memory space and
- iii) Store data into the created memory.
Types of an Array ?
There are two types of arrays in Java they are −
- i) One dimensional array and
- ii) Two dimensional arrays
One Dimensional Array ?
➦A list of items group in a single variable name with only one index is called one Dimensional array.
Declaration of an Array ?
We can declare an array in java using subscript operator. The general forms is
is equivalent to
Here, datatype is valid java datatype and
var_name is the name of the array.
Create memory space Array ?
After declaration of an array, we must allocate a memory space for the declared array. This is done with the help of new operator. The general form is:
array_name = new datatype[size];
For Example :
number = new int;
avg = new float;
0 0 0 0 0
Element at index 0 : 10 Element at index 1 : 20 Element at index 2 : 30 Element at index 3 : 40 Element at index 4 : 50
1.9 2.9 3.4 3.5 Total is 11.7 Max is 3.5
Two dimensional arrays :
A list of items group in a single variable name with two indexes(row and column size) is called two dimensional array.
10 20 30 40 50 60 70 80 90 11 21 31
Length of row 1: 3 Length of row 2: 4 Length of row 3: 1
Enter Numer of Row for Array (max 10) : 3 Enter Number of Column for Array (max 10) : 3 Enter 9 Array Elements : 1 2 3 4 5 6 7 8 9 The Array is : 1 2 3 4 5 6 7 8 9