Question

Bonus 1 • Write a java program to transpose a matrix mat[N][M], where: 1) You ask the user to input N and M 2) You then ask the user to input the matrix row by row 3) You transpose the matrix 4) You output the transpose to the user

Answer 1

import java.util.Scanner;

public class Transpose {

    public static void transpose(int[][] arr) {
        int temp;
        for (int i = 0; i < arr.length; ++i) {
            for (int j = 0; j < i; ++j) {
                temp = arr[i][j];
                arr[i][j] = arr[j][i];
                arr[j][i] = temp;
            }
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter number of rows: ");
        int N = in.nextInt();
        System.out.print("Enter number of columns: ");
        int M = in.nextInt();
        int[][] arr = new int[N][M];
        for (int i = 0; i < arr.length; ++i) {
            for (int j = 0; j < arr[i].length; ++j) {
                System.out.print("Enter an element at row " + i + " and column " + j + ": ");
                arr[i][j] = in.nextInt();
            }
        }
        transpose(arr);
        System.out.println("Transposed matrix is");
        for (int i = 0; i < arr.length; ++i) {
            for (int j = 0; j < arr[i].length; ++j) {
                System.out.print(arr[i][j] + " ");
            }
            System.out.println();
        }
    }
}

Enter number of rows: 3 Enter number of columns: 4 Enter an element at row 0 and column 0: Enter an element at row 0 and column 1: Enter an element at row 0 and column 2: Enter an element at row 0 and column 3: Enter an element at row 1 and column 0:1 Enter an element at row 1 and column 1: Enter an element at row 1 and column 2: Enter an element at row 1 and column 3 : Enter an element at row 2 and column 0:2 Enter an element at row 2 and column 1: Enter an element at row 2 and column 2: Enter an element at row 2 and column 3: Transposed matrix4 is 2 1 7 2 3 2 5 4 1 3 9 2