08 Arrays

8.1 | Arrays

An array is a data structure that stores a collection of values of the same data type. Values stored in the array are accessible through the array index

//Declaring an array of integers

int arr1[];

//Creating an integer array with values

int[] arr0 = {2,3,4,5,6,7};

//Creating an integer array which can hold 100 integers

int arr2[] = new int[100];

//Or,

int arraySize = 100;

int arr3[] = new int[arraySize];

//Assigning values to the array

arr3[0] = 1;

arr3[1] = 2;

//Creating a string array which can hold 100 values

String arr4[] = new String[100];

//Assigning values to the array

arr4[0] = "This";

arr4[1] = "is a string array by";

arr4[2] = "testinganswers.com";

//Accessing array values by using for loop

for(int i=0;i<arr3.length; i++){

     System.out.println("arr3["+i+"] = "+arr3[i]);

}

//Or by using for each loop,

for(int element:arr3){

    System.out.println(element +",");

}

//Copying array

int[] arr5 = arr3;

String[] arr6 = arr4;

8.1.1 | Multi-dimensional Arrays

Multi-dimensional arrays are arrays of an array. They use more than one index to store and access values.

//Declaring a multi-dimensional array

int[][] arr0;

//Creating a multi-dimensional array

int[][] arr1 = {

                       {1,2,3}

                       {4,5,6}

                       {7,8,9}

                    };

//Creating a multi-dimensional array of size 2*3

int[][] arr2 = new int[2][3];

//Creating a multi-dimensional array using variables

int arrayXsize = 3;

int arrayYsize = 3;

int[][] arr3 = new int[arrayXsize][arrayYsize];

//Assigning values to multi-dimensional arrays

arr3[0][0] = 1;

arr3[0][2] = 3;

//Accessing values from multi-dimensional arrays

for(int i=0;i<arr2.length;i++){

    for(int j=0;j<arr2[i].length;j++){

         System.out.println("arr2["+i+"]["+j+"] = "+arr2[i][j]);

    }

}

//Copying multi-dimensional arrays

int[][] arr4 = arr3;