Java Arrays

Arrays are used to store multiple values in a single variable, instead of declaring many separate variables for each value.

To declare an array, define the variables type with Square brackets shown below:

String[] names; //array of String 
int[] values; //array of integers

Now we have declared a variable that holds an array of strings. To insert values to it, we can use an array literal-place the values in a comma-separated list, inside curly braces

int[ ] values = {1, 2, 3, 4,......,n}; // Array of integers

String names = {"Dhoni","john","kamal","ram","devid"}; //Array String values

Access the Elements of an Array

you access an array element by referring to the index element. the example program will show you how to access the elements from the array:

public class cricket{
  public static void main(String[] args) {

    String[] fvrt_palyer= {"Dhoni", "Virat", "sachin", "yuvi"}; //Array of string values
                                                                
    System.out.println(fvrt_palyer[0]);  // here access the elements from the array by  index values
  }
}

Change an Array Element:

To change the value of a specific element, refer to the index number:

fvrt_palyer[0]= "rahul";

Example :

public class cricket{
  public static void main(String[] args) {
    String[] fvrt_palyer= {"Dhoni", "Virat", "sachin", "yuvi"}; //Array of string values
    fvrt_palyer[0]= "rahul"; //here change the index 0 value in the array 
    System.out.println(fvrt_palyer[0]);  // here access the elements from the array by  index values
  }
}

Array Length

To find out how many elements an array has, use the length property

Example:

System.out.println(fvrt_palyer.length); // here display the output how many elements in the array by using length

Loop Through an Array

You can loop through the array elements with the for loop, and use the length property to specify how many times the loop should run.

The following example outputs all elements in the fvrt_palyer array:

public class cricket{
  public static void main(String[] args) {
    String[] fvrt_palyer= {"Dhoni", "Virat", "sachin", "yuvi"}; //Array of string values
	for (int i = 0; i < fvrt_palyer.length; i++) {
      	System.out.println(fvrt_palyer[i]);
    	
	}
    }
}
The output will be:
Dhoni
Virat
sachin
yuvi

Loop Through an Array with For-Each

There is also a "for-each" loop, which is used exclusively to loop through elements in arrays.

Syntax:

for (type variable : arrayname) {
  ...
}

The following example outputs all elements in the cars array, using a "for-each" loop:

Example:

public class cricket{
  public static void main(String[] args) {
    String[] fvrt_palyer= {"Dhoni", "Virat", "sachin", "yuvi"};
    for (String i : fvrt_palyer) {
      System.out.println(i);
    }    
  }
}

output:
Dhoni
Virat
sachin
yuvi

The example above can be read like this: for each String element (called i - as in index) in fvrt_palyer, print out the value of i.

If you compare the for loop and for-each loop, you will see that the for-each method is easier to write, it does not require a counter (using the length property), and it is more readable.

Multidimensional Arrays

A multidimensional array is an array containing one or more arrays. To create a two-dimensional array, add each array within its own set of curly braces.

Example:

int[][] values= { {1, 2, 3, 4}, {5, 6, 7} }; 

values is now an array with two arrays as its elements. To access the elements of the values array, specify two indexes: one for the array, and one for the element inside that array.

This example accesses the third element (2) in the second array (1) of values.

Example

public class main(){
    piblic static void main(string args[]){
        int[][] values= { {1, 2, 3, 4}, {5, 6, 7} };
        int x = values[1][2]; 
        System.out.println(x); 
     }
  }
  Outputs 7 

We can also use a for loop inside another for loop to get the elements of a two-dimensional array (we still have to point to the two indexes).

Example:

public class Main { 
	public static void main(String[] args) {
		int[][] values= { {1, 2, 3, 4}, {5, 6, 7} }; 
		for (int i = 0; i < values.length; ++i) { 
			for(int j = 0; j < values[i].length; ++j) { 
				System.out.println(values[i][j]); 
			}
 		}
	 } 
}