Question

java

Write method that takes a 2D square array and two integer values that represent the indices of the two columns. Method swaps the first two columns.

int[][] in = {{1,2,3}, {3,2,4}, {4,2,7}};

would output 213234247

public static void swap(int[][] in, int index1, int index2) {

Answer 1

public class SwapColumns {

    public static void swap(int[][] in, int index1, int index2) {
        for (int i = 0; i < in.length; i++) {
            int temp = in[i][index1];
            in[i][index1] = in[i][index2];
            in[i][index2] = temp;
        }
    }

    public static void main(String[] args) {
        int[][] in = {{1, 2, 3}, {3, 2, 4}, {4, 2, 7}};
        System.out.println("Original matrix");
        for (int i = 0; i < in.length; i++) {
            for (int j = 0; j < in[i].length; j++) {
                System.out.print(in[i][j] + " ");
            }
            System.out.println();
        }
        swap(in, 0, 1);
        System.out.println("\nModified matrix");
        for (int i = 0; i < in.length; i++) {
            for (int j = 0; j < in[i].length; j++) {
                System.out.print(in[i][j] + " ");
            }
            System.out.println();
        }
    }
}