[Solved] Shift all elements in a 2-dimensional array by column index

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This program uses a logic in which we rotate an array by reversing array in parts. First we will reverse array upto index location and then reverse remaining array ( index+1 to last element of array).
After completing above two steps we call again reverse function but this time on whole of the array that gives us the required output.

Below is the code that will help in understanding above logic described.

public class ShiftTwoDArray {

    public static void main(String[] args) {
        int[][] x = {   { 1, 2, 3, 4, 5, 6, 7 }, 
                        { 1, 2, 3, 4, 5, 6, 7 }, 
                        { 1, 2, 3, 4, 5, 6, 7 },
                        { 1, 2, 3, 4, 5, 6, 7 } 
                    };

        int index = 3;
        int i, j;
        // System.out.println(x.length);
        System.out.println("Before");
        for (i = 0; i < x.length; i++) {
            for (j = 0; j < x[i].length; j++) {
                System.out.print(x[i][j] + "  ");
            }
            System.out.println();
        }
        rotate(x, index);

        System.out.println("\nAfter");
        for (i = 0; i < x.length; i++) {
            for (j = 0; j < x[i].length; j++) {
                System.out.print(x[i][j] + "  ");
            }
            System.out.println();
        }
    }

    /**
     * @param x
     * @param index
     * calls rotateUtil on each row
     */
    private static void rotate(int[][] x, int index) {
        for (int i = 0; i < x.length; i++) {
            rotateUtil(x[i], index);
        }
    }

    /**
     * @param x
     * @param index
     * reverse array in parts and then reverse whole array
     */
    private static void rotateUtil(int[] x, int index) {
        reverse(x, 0, index);
        reverse(x, index + 1, x.length - 1);
        reverse(x, 0, x.length - 1);
    }

    /**
     * @param x
     * @param start
     * @param end
     * reverse an array
     */
    private static void reverse(int[] x, int start, int end) {
        int temp = 0;
        while (start < end) {
            temp = x[start];
            x[start] = x[end];
            x[end] = temp;
            start++;
            end--;
        }
    }
}

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solved Shift all elements in a 2-dimensional array by column index