Java - how to rotate square array (two-dimensional) by 90 degree to the right?

Question

So, how should it work. I input "n" and "m" to make two-dimensional matrix with n*m resolution. I need to rotate it by 90 degrees to the right to make it somehow like that image made in paint:

I wrote some code but i cant really make it working - looks like it is easy but every time i try to get it working i get "outofboundsexception". Here it is:

 import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s1 = new Scanner(System.in);
        int n = s1.nextInt();
        int m = s1.nextInt();
        System.out.println();
        int[][] array = new int[n][m];
        int[][] ar = new int[n][m];
        for(int i = 0; i < array.length; i++) {
            for(int j = 0; j < array[n - 1].length; j++) {
                array[i][j] = s1.nextInt();
            }
        }
        System.out.println("INPUT ARRAY :");
        System.out.println();
        for(int i = 0; i < array.length; i++) {
            for (int j = 0; j < array[n - 1].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
        /* here is the main actions with the array begin*/
        for(int i = 0; i < array.length; i++) {
            for(int j = 0; j < array[n - 1].length; j++) {
                ar[i][j]=array[n - j - 1][i];
            }
        }
        /*the end of actions with the array*/
        System.out.println("TASK ARRAY :");
        System.out.println();
        for(int i = 0; i < ar.length; i++) {
            for (int j = 0; j < rr[n - 1].length; j++) {
                System.out.print(ar[i][j] + " ");
            }
            System.out.println();
        }
    }


}

What exactly am I doing wrong?

Answer 1

Here's the correct version of your program, with all the for-loop indices fixed, and the printing moved into a separate method.

public class Main {
    static void print(String title, int[][] array) {
        System.out.println(title);
        System.out.println();
        for (int i = 0; i < array.length; i++) {
            for (int j = 0; j < array[i].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }

    public static void main(String[] args) {
        Scanner s1 = new Scanner(System.in);
        int m = s1.nextInt();
        int n = s1.nextInt();
        System.out.println();
        int[][] array = new int[m][n];
        int[][] ar = new int[n][m];
        for(int i = 0; i < array.length; i++) {
            for(int j = 0; j < array[i].length; j++) {
                array[i][j] = s1.nextInt();
            }
        }

        print("INPUT ARRAY :", array);

        /* here is the main actions with the array begin*/
        for(int i = 0; i < array.length; i++) {
            for(int j = 0; j < array[i].length; j++) {
                ar[j][m - i - 1] = array[i][j];
            }
        }

        /*the end of actions with the array*/
        print("TASK ARRAY :", ar);
    }
}