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java array

Array:-Array is special type of variable which can store multiple values into a single variable but all the values must be same. In java array is object.
How to use array:-
1.     Declaration of array
2.     Create array
Syntax for array declaration:-
type arrayname[];
Or
type []arrayname;
For example
int a[];  or
int[]a;
Create array:-
a=new int[5];  or
int a[]=new int[5];
or
int []a=new int[5];
Example1:ArraY.java
class ArraY
{
public static void main(String[]args)
{
int []a;
a=new int[5];
System.out.println("length of array is : "+a.length);
}
}
Output:-
C:\JAVATECH>javac ArraY.java
C:\JAVATECH>java ArraY
length of array is : 5
Example2:- ArraY.java
class ArraY
{
public static void main(String[]args)
{
int []a;
a=new int[5];
System.out.println("length of array is : "+a.length);
System.out.println("Array elements are : ");
for(int i=0;i<a.length;i++)
{
a[i]=i+2;
System.out.println(a[i]);
}
}
}
Output:-
C:\JAVATECH>javac ArraY.java
C:\JAVATECH>java ArraY
length of array is : 5
Array elements are :
2
3
4
5
6
Example3:-ArraY.java
class ArraY
{
public static void main(String[]args)
{
int []a={10,20,30,40,50,60,70,80};
System.out.println("length of array is : "+a.length);
System.out.println("Array elements are : ");
for(int i=0;i<a.length;i++)
{
System.out.print(a[i]);
}
}
}
Output:-
C:\JAVATECH>javac ArraY.java
C:\JAVATECH>java ArraY
length of array is : 8
Array elements are:
10 20 30 40 50 60 70 80
2-D array:-two D array is used for creating table or matrix.
How to use array:-
1.     Declaration of array
2.     Create array
Syntax for array declaration:-
type arrayname[][];
Or
type [][]arrayname;
For example
int a[][];  or
int[][]a;
Create array:-
a=new int[3][3];  or
int a[][]=new int[3][3];
or
int [][]a=new int[3][3];

 Example1:- Test2D.java

 class Test2D
{
public static void main(String[]args)
{
int a[][]={{10,20,30},{40,50,60}};
int i,j;
System.out.println("matrix is");
for(i=0;i<=1;i++)
{
for(j=0;j<=2;j++)
{
System.out.print(a[i][j]+"\t");
}
System.out.println();
}
}
}

 Output:-
C:\javatech>javac Test2D.java
C:\javatech>java Test2D
matrix is
10      20      30

40      50      60

Example2:- Test2D.java
class Test2D
{
public static void main(String[]args)
{
System.out.println("Demo of 2 D array");
System.out.println("2 D array Declared");
int a[][];
int[][]b=new int[3][5];
a=new int[2][4];
System.out.println("2 D array ceated");
System.out.println("length of a matrix : "+a.length);
System.out.println("length of b matrix : "+b.length);
System.out.println("length of a[0] object matrix : "+a[0].length);
System.out.println("length of b[0] object matrix : "+b[0].length);
}
}
Output:-
C:\JAVATECH>javac Test2D.java
C:\JAVATECH>java Test2D
Demo of 2 D array
2 D array Declared
2 D array ceated
length of a matrix : 2
length of b matrix : 3
length of a[0] object matrix : 4
length of b[0] object matrix : 5
Example3:- Test2D.java
class Test2D
{
public static void main(String[]args)
{
System.out.println("Demo of 2 D array");
int a[][];
a=new int[2][2];

for(int i=0;i<2;i++)
{
for(int j=0;j<2;j++)
{
a[i][j]=i+j;
System.out.print(a[i][j]+"\t");
}
System.out.println();
}
}
}
Output:-
C:\JAVATECH>javac Test2D.java
C:\JAVATECH>java Test2D
Demo of 2 D array
0       1

1       2
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