# Java Program to Rotate Matrix Elements

In this article, we will understand how to rotate matrix elements. A matrix is representation of the elements in rows and columns. Matrix rotation is shifting the position of each element of the matrix by 1 position towards it’s right or left.

Below is a demonstration of the same −

Suppose our input is

The matrix is defined as
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16

The desired output would be

The matrix after one rotation:
5 1 2 3
9 10 6 4
13 11 7 8
14 15 16 12

## Algorithm

Step 1 - START
Step 2 - Declare an integer matrix namely input_matrix and declare four integer values namely row, column, previous, next.
Step 3 - Define the values.
Step 4 - Iterate over each element of the matrix using a while loop and shift the position of each element by one position to the right using multiple for-loops and store the matrix.
Step 5 - Display the result
Step 5 - Stop

## Example 1

Here, the input is being entered by the user based on a prompt.

public class RotateMatrix {
static int Rows = 4;
static int Columns = 4;
public static void main(String[] args) {
int input_matrix[][] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12},
{13, 14, 15, 16}
};
System.out.println("The input_matrix is defined as ");
for (int i = 0; i < Rows; i++) {
for (int j = 0; j < Columns; j++)
System.out.print( input_matrix[i][j] + " ");
System.out.print("\n");
}
int m = Rows, n = Columns;
int row = 0, column = 0;
int previous, current;
while (row < m && column < n) {
if (row + 1 == m || column + 1 == n)
break;
previous = input_matrix[row + 1][column];
for (int i = column; i < n; i++) {
current = input_matrix[row][i];
input_matrix[row][i] = previous;
previous = current;
}
row++;
for (int i = row; i < m; i++) {
current = input_matrix[i][n-1];
input_matrix[i][n-1] = previous;
previous = current;
}
n--;
if (row < m) {
for (int i = n-1; i >= column; i--) {
current = input_matrix[m-1][i];
input_matrix[m-1][i] = previous;
previous = current;
}
}
m--;
if (column < n) {
for (int i = m-1; i >= row; i--) {
current = input_matrix[i][column];
input_matrix[i][column] = previous;
previous = current;
}
}
column++;
}
System.out.println("\nThe input_matrix after one rotation: ");
for (int i = 0; i < Rows; i++) {
for (int j = 0; j < Columns; j++)
System.out.print( input_matrix[i][j] + " ");
System.out.print("\n");
}
}
}

## Output

The input_matrix is defined as
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16

The input_matrix after one rotation:
5 1 2 3
9 10 6 4
13 11 7 8
14 15 16 12

## Example 2

Here, the integer has been previously defined, and its value is accessed and displayed on the console.

public class RotateMatrix {
static int Rows = 4;
static int Columns = 4;
static void Rotate_matrix(int m,
int n, int matrix[][]) {
int row = 0, column = 0;
int previous, current;
while (row < m && column < n) {
if (row + 1 == m || column + 1 == n)
break;
previous = matrix[row + 1][column];
for (int i = column; i < n; i++) {
current = matrix[row][i];
matrix[row][i] = previous;
previous = current;
}
row++;
for (int i = row; i < m; i++) {
current = matrix[i][n-1];
matrix[i][n-1] = previous;
previous = current;
}
n--;
if (row < m) {
for (int i = n-1; i >= column; i--) {
current = matrix[m-1][i];
matrix[m-1][i] = previous;
previous = current;
}
}
m--;
if (column < n) {
for (int i = m-1; i >= row; i--) {
current = matrix[i][column];
matrix[i][column] = previous;
previous = current;
}
}
column++;
}
System.out.println("\nThe matrix after one rotation: ");
for (int i = 0; i < Rows; i++) {
for (int j = 0; j < Columns; j++)
System.out.print( matrix[i][j] + " ");
System.out.print("\n");
}
}
public static void main(String[] args) {
int input_matrix[][] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12},
{13, 14, 15, 16}
};
System.out.println("The matrix is defined as ");
for (int i = 0; i < Rows; i++) {
for (int j = 0; j < Columns; j++)
System.out.print( input_matrix[i][j] + " ");
System.out.print("\n");
}
Rotate_matrix(Rows, Columns, input_matrix);
}
}

## Output

The matrix is defined as
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16

The matrix after one rotation:
5 1 2 3
9 10 6 4
13 11 7 8
14 15 16 12