Two-dimensional array in java

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Programming
Created By: Anonymous

What is 2-D Array?
• Array of Arrays.
• 2-D array usually represented with rows and columns

2-D Array Declaration
• We can declare 2-D array in following ways
type[][] referencevariable;
or
type referencevariable[][];
For example:
int marks[][];
Each element in the 2-D Array must be the same type.

Creation of 2-D Array
arrayreferencevariable = new type[value][value];
For example :
marks = new int[3][4];

More on 2-D Array Creation
marks = new int[][] // incorrect;
marks= new int[][4] // incorrect;
marks = new int[3][] // correct;

2-D array in form of rows and columns:
marks=new int[3][4];

Initialization of 2-D Array
• After array creation we can initialize the 2-D array like this :
• Arrayvariable[row][column]= value;
• For example lets initialize the marks array :

marks[0][0]=8; marks[0][1]=9; marks[0][2]=10; marks[0][3]=7;
8 9 10 7Row 0
Col 0 Col 1 Col 3 Col 4
12 21 30 7
31 45 10 40
Row 1
Row 2

8 9 10 7
12 21 30 7
31 45 10 40
Col 0 Col 2 Col 3Col 1
Row 0
Row 1
Row 2
Now if you want to access any element from 2-D array
System.Out.Println(marks[1][2]);
output = 30
System.Out.Println(marks[0][0]);
output = 8

We can also initialize the array at the time of
array creation
int[][] marks = new int{
{1,2,0,5},
{4,5,1,4},
{7,6,5,9}
}

How we can get array length
marks.length // tell us rows.
marks[0].length // tell us columns.

Two-dimensional array in java

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