The array is a collection similar data type.  Java provides a data structure, the array, which stores a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.


Array in Java


Creating Arrays:

dataType[] arrayRefVar;
arrayRefVar = new dataType[arraySize];
or 
dataType[] arrayRefVar = {value0, value1, ..., valuen};
Example -:   double[ ] myList = new double[10];


Types of Array in java

There are two types of array.

  • Single Dimensional Array
  • Multidimensional Array

Example of Single Dimensional array

class Testarray{  
public static void main(String args[]){  
  
int a[]=new int[5];//declaration and instantiation  
a[0]=10;//initialization  
a[1]=20;  
a[2]=70;  
a[3]=40;  
a[4]=50;  
  
//printing array  
for(int i=0;i<a.length;i++)//length is the property of array  
System.out.print(a[i]+ " ");  
  
}

 

     

Output-:  10   20    70     40     50

 

Multidimensional array in java

Declare of multidimensional array: dataType[][] arrayRefVar; (or)  

dataType [][]arrayRefVar; (or)  
dataType arrayRefVar[][]; (or)  
dataType []arrayRefVar[];
Example-:  int[][] arr=new int[3][3];  //3 row and 3 column  
Initialized multidimensional array
arr[0][0]=1;  
arr[0][1]=2;  
arr[0][2]=3;  
arr[1][0]=4;  
arr[1][1]=5;  
arr[1][2]=6;  
arr[2][0]=7;  
arr[2][1]=8;  
arr[2][2]=9;

Example of multidimensional array 

class Sample {
   public static void main(String args[]) {
      //declaring and initializing 2D array  
      int arr[][]={{1,2,3},{2,4,5},{4,4,5}};  
  
      //printing 2D array  
      for(int i=0;i<3;i++){  
         for(int j=0;j<3;j++){  
         System.out.print(arr[i][j]+" ");  
      }  
      System.out.println();  
   } 
}


Example of the array using for loop

public class Sample {
 
   public static void main(String[] args) {
      double[] myList = {1.9, 2.9, 3.4, 3.5};
 
      // Print all the array elements
      for (double element: myList) {
         System.out.println(element);
      }
   }
}

Output-: 

Advantage of Java Array
Disadvantage of Java Array

1.9

2.9

3.4

3.5


Code Optimization: It makes the code optimized, we can retrieve or sort the data easily.


Random access: We can get any data located at any index position.


Size Limit: We can store the only fixed size of elements in the array. It doesn't grow its size at runtime. To solve this problem, collection framework is used in java.

  Modified On Feb-23-2018 01:26:04 AM

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