# Java create Identity matrix

In this tutorial, you will learn how to create an identity or unit matrix.

In this tutorial, you will learn how to create an identity or unit matrix.

## Java create Identity matrix

In this tutorial, you will learn how to create an identity or unit matrix.

An identity matrix is a square matrix, of size n x n in which all the elements of the principal diagonal are ones and all other elements are zeros. Here, we are going to create the unit matrix of arbitrary dimensions say (n*n). The given code accepts the size(n) of unit matrix and display the matrix of  n x n. Suppose, n is 3, then the unit matrix of size 3 x 3 should be:

```1 0 0
0 1 0
0 0 1
```

Example:

```import java.util.*;
class UnitMatrix
{
public static int[][] create(int size) {
int[][] matrix = new int[size][size];
for(int i = 0; i < size; i++)
for(int j = 0; j < size; j++)
matrix[i][j] = (i == j) ? 1 : 0;
return matrix;
}

public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
System.out.println("Enter size of matrix: ");
int size=input.nextInt();
int matrix[][]=create(size);

for (int i=0 ; i < matrix.length ; i++)
{ System.out.println();
for (int j=0 ; j < matrix[i].length ; j++){
System.out.print(matrix[i][j]+" ");
}
}
}
}
```

Output:

```Enter size of matrix:
5

1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0
0 0 0 0 1
```