Transposing a matrix from a 2D array

Question

I\'m self teaching myself some java and I\'m stuck on creating a 2D array that initializes it with random values and then creates the transpose of the array.

An ex

Answer 1

You can use the below class it has most of the methods you want.

/**
 * Class representing square matrix of given size.
 * It has methods to rotate by 90, 180 and 270
 * And also to transpose and flip on either axis.
 * 
 * I have used both space efficient methods in transpose and flip
 * And simple but more space usage for rotation. 
 * 
 * This is using builder pattern hence, you can keep on applying
 * methods say rotate90().rotate90() to get 180 turn.
 * 
 */
public class Matrix {

    private int[][] matrix;
    final int size;

    public Matrix(final int size) {
        this.size = size;
        matrix = new int[size][size];

        for (int i=0;i 3) {
                    sb.append("\t");
                }
            }
            sb.append("|\n");
        }

        return sb.toString();
    }

    public static void main(String... args) {
        Matrix m = new Matrix(3);
        System.out.println(m);

        //transpose and flipHorizontal is 270 turn (-90)
        System.out.println(m.transpose());
        System.out.println(m.flipHorizontal());

        //rotate 90 further to bring it back to original position
        System.out.println(m.rotate90());

        //transpose and flip Vertical is 90 degree turn
        System.out.println(m.transpose().flipVertical());
    }
}

Output:

|0|1|2|
|3|4|5|
|6|7|8|

|0|3|6|
|1|4|7|
|2|5|8|

|2|5|8|
|1|4|7|
|0|3|6|

|0|1|2|
|3|4|5|
|6|7|8|

|6|3|0|
|7|4|1|
|8|5|2|