Question

Homework 12: Matrix Operations Read Chapter 8 on Multi-dimensional arrays. This chapter has sample code that will be helpful with this assignment. Write methods that allow the user to operate on matrices. Start by writing your main() method, then getting the menu working, then get printMatrix() working. A. Program Description A matrix is a two dimensional array of numbers. For example: 10 5 7 40 29 30 5 77 1 4 30 1 10 603 OOPOP 1 Your program should do the following: 1. Prompt the user for the number of rows and the number of columns in the matrix. The maximum number of rows or columns is 4, the minimum is 1. Your program will ask the user what size matrix to create. You should validate the inputs and display an error message if an invalid input was detected, then let the user try again. 2. Generate a matrix having the dimensions specified by the user. 3. Assign integers to each element of the matrix as follows (first row starts with o, increment by one for each column; second row starts with 10, increment by one for each column;...): If the user enters 3 rows and 2 columns, the matrix is initialized with exactly the following values: 10 20 1 11 21 If the user enters 4 rows and 4 columns, the matrix is initialized with exactly these values: 3 13 10 20 30 1 11 21 31 2 12 22 32

/***************************************************

  Name: 
  Date: 
  Homework #7
  
  Program name:        HexUtilitySOLUTION
  Program description: Accepts hexadecimal numbers as input.
                       Valid input examples: F00D, 000a, 1010, FFFF, Goodbye, BYE
                       Enter BYE (case insensitive) to exit the program.
  
****************************************************/

import java.util.Scanner;

public class HexUtilitySOLUTION {

  public static void main(String[] args) {

    // Maximum length of input string
    final byte INPUT_LENGTH = 4;

    String userInput = "";                   // Initialize to null string
    Scanner input = new Scanner(System.in);

    // Process the inputs until BYE is entered
    do {
      // Input a 4 digit hex number
      System.out.print("\nEnter a hexadecimal string, or enter BYE to quit:  ");
      userInput = input.next().toUpperCase();

      // Process the input
      switch (userInput) {

        case "BYE": break;
            
        default:        if (userInput.length() != INPUT_LENGTH) {
                          // Input length is incorrect
                          System.out.printf("      The input %s is the wrong length, it should be %d characters long.\n", userInput, INPUT_LENGTH);
                          break;
                        }

                        // Input length is correct
                        if (isValidHex(userInput)) {  //Call method isValidHex
                          // The input is a valid hexadecimal string
                          System.out.printf("      The input %s is a valid hexadecimal value.\n", userInput);
                        }

                        else {
                          // String is either the wrong length or is not a valid hexadecimal string
                          System.out.printf("      The input %s is not a valid hexadecimal value.\n", userInput);
                        }
                        break;
        }
    } while (!userInput.equals("BYE"));

    // Exit the program
    System.out.println("\nGoodbye!");
    input.close();
  }
 
  // Method to validate the input.
  // This method returns true or false to the caller (main).
  // This method accepts one parameter - the user input.
  public static boolean isValidHex(String userIn) {
    boolean isValid = false;
        
    // The length is correct, now check that all characters are legal hexadecimal digits
    for (int i = 0; i < userIn.length(); i++) {
      char thisChar = userIn.charAt(i);

      // Is the character a decimal digit (0..9)? If so, advance to the next character
      if (Character.isDigit(thisChar)) {
        isValid = true;
      }

      else {
        // Character is not a decimal digit (0..9), is it a valid hexadecimal digit (A..F)?
        if ((thisChar >= 'A') && (thisChar <= 'F')) {
          isValid = true;
        }
        else {
          // Found an invalid digit, no need to check other digits, exit this loop
          isValid = false;
          break;
        }
      }
    }
        
    // Returns true if the string is a valid hexadecimal string, false otherwise
    return isValid;
  }
}

Answer 1

Note: Could you plz go through this code and let me know if u need any changes in this.Thank You
=================================

// Matrix.java

import java.util.Scanner;

public class Matrix {

   public static void main(String[] args) {
       int row, col;
       char chioice;

       /*
       * Creating an Scanner class object which is used to get the inputs
       * entered by the user
       */
       Scanner sc = new Scanner(System.in);

       while (true) {
           // Getting the input entered by the user
           System.out.print("Enter no of rows :");
           row = sc.nextInt();
           if (row < 1 || row > 4) {
               System.out.println("** Invalid.Must be between 1-4 **");
           } else
               break;

       }

       while (true) {
           // Getting the input entered by the user
           System.out.print("Enter no of cols :");
           col = sc.nextInt();
           if (col < 1 || col > 4) {
               System.out.println("** Invalid.Must be between 1-4 **");
           } else
               break;

       }
       int array[][] = new int[row][col];
       for (int i = 0; i < row; i++) {

           for (int j = 0; j < col; j++) {
               System.out.print("Enter Element in row#" + (i) + " column#"
                       + (j) + ":");
               array[i][j] = sc.nextInt();
           }
       }

       while (true) {
           System.out.println("\nP Print matrix");
           System.out.println("R Reverse Rows ");
           System.out.println("S ColumnSum");
           System.out.println("T Transpose");
           System.out.println("Q Quit");
           chioice = sc.next().charAt(0);
           switch (chioice) {
           case 'P':
           case 'p': {
               printMatrix(array);
               continue;
           }
           case 'R':
           case 'r': {
               reverseMatrix(array);
               continue;
           }

           case 'S':
           case 's': {
               columnSum(array);
               continue;
           }
           case 'T':
           case 't': {
               transpose(array);
               continue;
           }
           case 'Q':
           case 'q': {
               break;
           }
           default: {
               System.out.println("** Invalid Choice **");
           }

           }
           break;
       }

   }

   private static void transpose(int[][] array) {
   for(int i=0;i<array[0].length;i++)
   {
   for(int j=0;j<array.length;j++)
   {
   System.out.print(array[j][i]+" ");
   }
   System.out.println();
   }

      
   }

   private static void columnSum(int[][] array) {
       int sum=0;
       for (int i = 0; i < array.length; i++) {
           for (int j = 0; j < array[0].length; j++) {
               System.out.print(array[i][j] + " ");
           }
           System.out.println();
       }
      
       for(int j=0;j<array[0].length;j++)
       {
           sum=0;
           for(int i=0;i<array.length;i++)
           {
              
               sum+=array[i][j];
           }
           System.out.print(sum+" ");
          
       }
       System.out.println();
      
   }

   private static void reverseMatrix(int[][] array) {
       for(int j = 0; j < array.length; j++){
       for(int i = 0; i < array[j].length / 2; i++) {
       int temp = array[j][i];
       array[j][i] = array[j][array[j].length - i - 1];
       array[j][array[j].length - i - 1] = temp;
       }
       }
      
   }

   private static void printMatrix(int[][] array) {
       for (int i = 0; i < array.length; i++) {
           for (int j = 0; j < array[0].length; j++) {
               System.out.print(array[i][j] + " ");
           }
           System.out.println();
       }

   }

}
=======================================

Output:

Enter no of rows :3
Enter no of cols :2
Enter Element in row#0 column#0:0
Enter Element in row#0 column#1:1
Enter Element in row#1 column#0:10
Enter Element in row#1 column#1:11
Enter Element in row#2 column#0:20
Enter Element in row#2 column#1:21

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
p
0 1
10 11
20 21

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
R

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
p
1 0
11 10
21 20

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
s
1 0
11 10
21 20
33 30

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
T
1 11 21
0 10 20

P Print matrix
R Reverse Rows
S ColumnSum
T Transpose
Q Quit
Q

=====================Could you plz rate me well.Thank You