Implementing a Java program to transpose rows and columns in a two-dimnesional array:

Original matrix: 1 2 3 4 5 6 7 8 9

Transposed matrix: 1 4 7 2 5 8 3 6 9

public class MatrixTransposer {
    public static void main(String[] args) {
        int[][] matrixData = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
        
        System.out.println("Original matrix:");
        displayMatrix(matrixData);
        
        System.out.println("\nTransposed matrix:");
        transposeAndDisplay(matrixData);
    }
    
    private static void displayMatrix(int[][] matrix) {
        for (int row = 0; row < matrix.length; row++) {
            for (int col = 0; col < matrix[row].length; col++) {
                System.out.print("\t" + matrix[row][col]);
            }
            System.out.println();
        }
    }
    
    private static void transposeAndDisplay(int[][] matrix) {
        for (int col = 0; col < matrix[0].length; col++) {
            for (int row = 0; row < matrix.length; row++) {
                System.out.print("\t" + matrix[row][col]);
            }
            System.out.println();
        }
    }
}

Output:

Original matrix:
	1	2	3
	4	5	6
	7	8	9

Transposed matrix:
	1	4	7
	2	5	8
	3	6	9

An incorrect implementation that modifies the oriignal aray during display:

public class IncorrectTranspose {
    public static void main(String[] args) {
        int[][] originalMatrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
        
        System.out.println("Original matrix:");
        for (int i = 0; i < originalMatrix.length; i++) {
            for (int j = 0; j < originalMatrix[i].length; j++) {
                System.out.print("\t" + originalMatrix[i][j]);
            }
            System.out.println();
        }
        
        System.out.println("\nTransposed matrix (with side effects):");
        for (int i = 0; i < originalMatrix.length; i++) {
            for (int j = 0; j < originalMatrix[i].length; j++) {
                int temporary = originalMatrix[i][j];
                originalMatrix[j][i] = temporary;
                System.out.print("\t" + originalMatrix[j][i]);
            }
            System.out.println();
        }
    }
}