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08 Arrays

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;

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