Arrays

An array can be defined as a collection of similar elements. Java supports three types of arrays namely

Single dimensional.
Double dimensional.
Multi dimensional.

A single dimensional array can be created in the following format.

Syntax:data_type array_name[] = new data_type[size];

(or)

data_type array_name[];

array_name = new data_type[size];

Example:

int x[] = new int[5]; (or) int x[];

x = new int[5];

class App10{

public static void main(String yck[])

{

int x[]=new int [5];

int i,k;

for(i=0,k=10;i<4;i++,k+=10)

x[i]=k;

System.out.println(“The elements in the array are ………”);

for(i=0;i<4;i++) //for(i=0;i<x.length;i++)

System.out.println(x[i]+” “);

}

output:

\>javac App10.java

\>java App10

The elements in the array are ………

10

20

30

40

Length property: Whenever you create an array in Java, automatically a special property called length is attached to it. The length property returns the size of the array.

Example: for(i=0; i<x.length; i++)

A double dimensional array is a matrix of rows and columns. A two dimensional array can be declared in the following format…

Syntax:data_type array_name[][]=new data_type array_name[rows][columns];

(or)

data_type array_name[][];

array_name = new data_type array_name[rows][columns];

class App11{

public static void main(String yck[])

{

int x[][]=new int [3][3];

int r,c;

for(r=0;r<=2;r++)

{

for(c=0;c<=2;c++)

{

if(r==c)

x[r][c]=1;

else

x[r][c]=0;

}

System.out.println(“The elements in the Matrix are ………”);

for(r=0;r<=2;r++) //for(r=0;r<x.length;r++)

{

for(c=0;c<=2;c++) //for(c=0;c<x[r].length;c++) <dd=””> System.out.print(x[r][c]+” “);</x[r].length;c++)>

System.out.println();

}

output:

\>javac App11.java

\>java App11

The elements in the Matrix are ………

1 0 0

0 1 0

0 0 1

class App12{

public static void main(String yck[])

{

int x[][]=new int [3][3];

int r,c,k;

for(r=0,k=1;r<=2;r++)

{

for(c=0;c<=2;c++,k++)

x[r][c]=k;

}

System.out.println(“The elements in the Matrix are ………”);

for(r=0;r<=2;r++) //for(r=0;r<x.length;r++)

{

for(c=0;c<=2;c++) //for(c=0;c<x[r].length;c++)

System.out.print(x[r][c]+” “);

System.out.println();

}

output:

\>javac App12.java

\>java App12

The elements in the Matrix are ………

1 2 3

4 5 6

7 8 9

A multidimensional array can be declared in the following format…..

Syntax:data_type array_name[][][]=new data_type array_name[x][y][z];

or

data_type array_name[][][];

array_name = new data_type array_name[x][y][z];

Note: Java allows you to create a variety of arrays with a fixed no. of rows and each row varies with different no. of cell’s.

Example: App13.java

class App13{

public static void main(String yck[])

{

int x[][]=new int [3][];

x[0]=new int[5];

x[1]=new int[2];

x[2]=new int[8];

int r,c,k;

for(r=0,k=1;r<=2;r++)

{

for(c=0;c<x[r].length;c++,k++) <dd=””> x[r][c]=k;</x[r].length;c++,k++)>

}

System.out.println(“The elements in the Matrix are ………”);

for(r=0;r<=2;r++) //for(r=0;r<x.length;r++)

{

for(c=0;c<x[r].length;c++) <dd=””> System.out.print(x[r][c]+” “);</x[r].length;c++)>

System.out.println();

}

output:

\>javac App13.java

\>java App13

The elements in the Matrix are ………

1 2 3 4 5

6 7

8 9 10 11 12 13 14 15

Arrays in Java Programming Language

Arrays

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