Java Array

 

Array

     ]  Collection Of Similar Data Type Stored In Continous Memory Location

     ]  Arrays  Are A Way To Store A List Of Items.

     ]  Array will store Multiple values in single variable.

Single Dimensional Array

A One -Dimensional Array Is,Essentially,A List Of Like -Typad Variables. To Create An Array In Java,You Use Three Steps:

·       Declare A Variable To Hold The Array

·       Create A New Array Object And Assign It To The Array Variable

·       Assigning Value

Declaring Array Variables

String dificultwords[];

Point hits[];

Int temps[];

Creating Array Objects

The Second step is to create an array object and assign it to that variable.There are two ways to do this

Ø Using new

Ø Directly initializing the contents of that array

String[] names=new String[10];

int[] temps=new int[99];

String[] fruits={"Apple","Orange","Banana","Pineapple',"Mango"};

accessing  array elements

Once you have an array with initial values, you can test and change the values in each slot of that array.

To get a value stored within an array, use the array subscript expression:

myArray[subscript];

 String []arr=new String[10];

arr[10]="eggplant";

Changing array Elements

Example

myarray[1]=15;

sentence[0]="The";

sentence[10]=sentence[0];

Example 1

class ArrayDemo

{

       int i;

       int arr[]={1,2,3,4,5,6,7,8,9,10};

       void result()

       {

       System.out.println("Array details \n");

       for(i=0;i<10;i++)

       {

         System.out.print(arr[i]+"\t");

       }

     }

      public static void main(String args[])

       {

          ArrayDemo d=new ArrayDemo ();

          d.result();

       }

}

 Output

//Average an Array of Values

class Average{

       public static void main (String args[]){

             double nums[]={10.1,11.2,12.3,13.4,14.5};

            double result=0;

            int i; 

             for(i=0;i<5;i++)

             result=result+nums[i];

             System.out.println("average is"+result/5);

}

}

 Output

Multidimensional Array

int coords[][]=new int[12][12];

coords[0][0]=1;

coords[0][1]=2;

class TwoD{

        public static void main (String args[]) {

                       int twoD[][]=new int[4][4];

                       int i,j,k=0;

                       for(i=0;i<4;i++)

                              for(j=0;j<4;j++){

                                            twoD[i][j]=k;

                                            k++;

                   }

              for(i=0;i<4;i++) {

                       for(j=0;j<4;j++)

                                     System.out.print(twoD[i][j]+" ");

                       System.out.println();

          }

   }

}

 Output

Ragged Array

Multidimensional array are faked as "array of array".it is also called ragged array.The Ragged Array has different rows and different lengths.

class TwoDAgain{

        public static void main (String args[]) {

                       int twoD[][]=new int[4][];

                       twoD[0]=new int[1];

                       twoD[1]=new int[4];

                       twoD[2]=new int[3];

               twoD[3]=new int[2];

                       int i,j,k=0;

                       for(i=0;i<4;i++)

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

                                            twoD[i][j]=k;

                                            k++;

                   }

              for(i=0;i<4;i++) {

                       for(j=0;j<twoD[i].length;j++)

                                     System.out.print(twoD[i][j]+" ");

                       System.out.println();

          }

   }

}

 Output