Arrays in Java
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The Array is used to group similar type of elements.
Following is how you declare an array.
type[] identifier;
or
type identifier[];
ex.
int[] intValuesArray;
Following is the syntax to initialize an Array
identifier = new type[size];
ex.
intValuesArray = new int[10];
You can do this in one line as shown below
int[] intValuesArray = new int[10];
Inline Initialization
You can assign values to array at the time of declaration itself as shown in following code
int intValuesArray[5]={1,2,3,4,5};
Reading & Writing
Following program explains you how to write data to an array and how to read from it
class Arrays {
public static void main(String[] args) {
int[] intValuesArray = new int[5]; //Declaration
// Writing to Array
intValuesArray[0] = 1;
intValuesArray[1] = 2;
intValuesArray[2] = 3;
intValuesArray[3] = 4;
intValuesArray[4] = 5;
// Reading from Array
int x = intValuesArray[1];
System.out.println("Value at 2nd position is: " + x);
}
}
Output:
Value at 2nd position is:2
Multi dimensional Arrays
Multi dimensional Arrays are Arrays of Arrays, these can be of any dimensions.
Following example shows you creating a two dimensional array and writing, reading data from and to the array.
public class TwoDimentionalArray {
public static void main(String[] args) {
int twoDimentionalArray[][] = new int[2][2]; //Declaration
// Writing to Two Dimensional Array
twoDimentionalArray[0][0] = 11;
twoDimentionalArray[0][1] = 12;
twoDimentionalArray[1][0] = 21;
twoDimentionalArray[1][1] = 22;
// Reading to Two Dimensional Array
System.out.println("Value at [0][0] position is: " + twoDimentionalArray[0][0]);
System.out.println("Value at [0][1] position is: " + twoDimentionalArray[0][1]);
System.out.println("Value at [1][0] position is: " + twoDimentionalArray[1][0]);
System.out.println("Value at [1][1] position is: " + twoDimentionalArray[1][1]);
}
}
Output:
Value at [0][0] position is: 11
Value at [0][1] position is: 12
Value at [1][0] position is: 21
Value at [1][1] position is: 22