Arrays.sort() not functioning properly in java

Question

so I have the following ClassSeat program where I have to automatically assign seats to students and sort their names alphabetically. I do not know if the sorting of the names is working properly in alphabetical order, my output does not seem to match my expected output. I have to use Arrays.sort() to sort out the names but here is what my output looks like:

My output:

Select Your Class Size!

A 6x5 Classroom or a 3X10 classroom?
 Enter '6x5' or '3x10' please!

3x10

Ok, so you have selected 3x10
Your classroom size looks like this:

XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX

Now Enter The Number Of Students!
8

Enter the first names of the 8 students!

Hussain
Omer
Zebra
Animal
here
k
l
m

The Names And Seat Location Of The Student Are As Follows:

Hussain Seat Location: (1)(1)
Omer Seat Location: (1)(2)
Zebra Seat Location: (1)(3)
Animal Seat Location: (2)(1)
here Seat Location: (2)(2)
k Seat Location: (2)(3)
l Seat Location: (3)(1)
m Seat Location: (3)(2)

Do You Want To Assign Seats By Alphabetical Order? (y/n)

y
Animal Seat Location: (1)(1)
Hussain Seat Location: (1)(2)
Omer Seat Location: (1)(3)
Zebra Seat Location: (2)(1)
here Seat Location: (2)(2)
k Seat Location: (2)(3)
l Seat Location: (3)(1)
m Seat Location: (3)(2)

Exit The Program? (y/n)

y

Expected Output:

Select Your Class Size!

A 6x5 Classroom or a 3X10 classroom?
 Enter '6x5' or '3x10' please!

3x10

Ok, so you have selected 3x10
Your classroom size looks like this:

XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX

Now Enter The Number Of Students!
8

Enter the first names of the 8 students!

Hussain
Omer
Zebra
Animal
here
k
l
m

The Names And Seat Location Of The Student Are As Follows:

Hussain Seat Location: (1)(1)
Omer Seat Location: (1)(2)
Zebra Seat Location: (1)(3)
Animal Seat Location: (2)(1)
here Seat Location: (2)(2)
k Seat Location: (2)(3)
l Seat Location: (3)(1)
m Seat Location: (3)(2)

Do You Want To Assign Seats By Alphabetical Order? (y/n)

y
Animal Seat Location: (1)(1) omer zebra
here Seat Location: (1)(2)
Hussain Seat Location: (1)(3)
k Seat Location: (2)(1)
l Seat Location: (2)(2)
m Seat Location: (2)(3)
omer Seat Location: (3)(1)
zebra Seat Location: (3)(2)

Exit The Program? (y/n)

y

Why is not sorting the names properly?

Code:

 // Import util packages
import java.util.*;

// Import io packages 
import java.io.*;

// Create a class and method
public class Main {
  public static void main(String[] args) {

    // Create a while loop so that once the user wants to exit the program, the loop breaks, and if the user does not want to exit the program, the program restarts
    while(true){
    
    // Clear the screen
    System.out.print("\033[H\033[2J");
    System.out.flush();

    // Create scanner object
    Scanner inp = new Scanner(System.in);

    // Create print statements
    System.out.println("Select Your Class Size!\n");
    System.out.println("A 6x5 Classroom or a 3X10 classroom?\n Enter '6x5' or '3x10' please!\n");

    // Create variables to be used in the print statements 
    String Class1 = "6x5";
    String Class2 = "3x10";

    // Create a double array variable with the limit of 1 so that it can be used to recognize the "x" in the string 
    Double input[] = new Double[1];

    // Allow the user to choose what classSize they would like
    String selectClassSize = inp.next();

    // Creat an indexofx to find the "x" in the selectClassSize variable
    int indexOfx = selectClassSize.indexOf('x');
    
    // Create a counter variable to count/find the "x"
    int xcount = 0;

    // Create a boolean variable that has the requirements in it, and finds the first index and the last index
    // Subtract 2 from the length because "x" will be located in the middle of a 3 word string
    boolean containsx = indexOfx == 0 || indexOfx == (selectClassSize.length() - 2);

    // Validate x at beginning or end 
    if (containsx) {

      // Use the double array and counter to find the "x" in the string 
      input[xcount] = Double.parseDouble(selectClassSize.replace("x", ""));
      
      // Create print statements 
      System.out.println("\nOk, so you have selected " + Class1);
      System.out.println("Your classroom size looks like this:\n");

      // Initialize variables to use in the for loop, start with the 6x5 classSize
      int rows = 6;
      int columns = 5;

      // Create a multi-dimensional array to include both the rows and columns
      int classSize[][] = new int [rows][columns];
      
      // Create a for loop to print a visual representation of the 6x5 classSize
      for(int i = 0; i < classSize[0].length; i++){
        for(int j = 0; j < classSize.length; j++){
            System.out.print("X");
      }
      System.out.println();
    }
      xcount++;

    // Otherwise, do the same thing for 3x10 classSize
    } else {
      System.out.println("\nOk, so you have selected " + Class2);
      System.out.println("Your classroom size looks like this:\n");

      // Initialize variables to use in the for loop, but this time for the 3x10 classSize
      int rows2 = 3;
      int columns2 = 10;
      int classSize2[][] = new int [rows2][columns2];
        for(int x = 0; x < classSize2[0].length; x++){
          for(int y = 0; y < classSize2.length; y++){
              System.out.print("X");
      }
      System.out.println();
      }
    }

    // Create a print statement
    System.out.println("\nNow Enter The Number Of Students!");

    // Create a scanner variable to allow the user to enter the number of students in the class 
    int numOfStudents = inp.nextInt();

    // Create a print statement 
    System.out.println("\nEnter the first names of the " + numOfStudents + " students!\n");

    // Initialize String array variables to be used in the for loop and inside the try-catch block 
    String[] names = new String[numOfStudents];
    String[] seats = new String[numOfStudents];

     try {

      // Initialize the new objects
      FileWriter fw = new FileWriter("StudentNames");
      BufferedWriter bw = new BufferedWriter(fw);
      
      // Create int variables to output the seat location 
      int row = 0;
      int column = 1; 
      
      // Use a for loop to allow the user to enter names, and the program to assign seats automatically, save both the information in a new textfile called "StudentNames"
      for (int x = 0; x < numOfStudents; x++) {
          names[x] = inp.next();

          // if "x" is validated to be found, basically call this boolean from before that checks the possiblity of "x"
          if(containsx) {

              // For the 6x5 classSize, if row is greater than 6 or equal to 6, start a new row and count the number of columns, accordingly 
              if(row >= 6) {
                  column++;

                  // Set row to 0
                  row = 0;
              }
          }

          // Otherwise, for the 3x10 classSize, if the row if greater or equal to 3, then start a new row and count the number of columns, accordingly
          else {
              if(row >= 3) {
                  column++;

                  // Set row to 0
                  row = 0;
              }
          }

          // Assign a array, and use Integer.toString to return the String with a specified Integer parameter (column) and (rows)
          seats[x] = "("+Integer.toString(column)+")" + "("+Integer.toString(++row)+")";

          // Write it onto the textfile called "StudentNames"
          bw.write(names[x]+" Seat Location: "+seats[x]);
          bw.newLine();
      }
      
      bw.close();
      fw.close();

      // Catch any errors
    } catch (Exception e) {
      System.out.println("An Error Occured!");
    }

    // Create another try-catch block to read the file 
     try {

      // Initialize the new objects
      FileReader fr = new FileReader("StudentNames");
      BufferedReader br = new BufferedReader(fr);

      String line = br.readLine();

      // Create a print statement 
      System.out.println("\nThe Names And Seat Location Of The Student Are As Follows:\n");
      
      // Start a while loop to output the data from the file
      while (line != null) {
          System.out.println(line);
          line = br.readLine();
        }

      br.close();
      fr.close();

      // Catch any errors
    } catch (Exception e1) {
      System.out.println("An Error Occured!");
    }

    // Create a print statement 
    System.out.println("\nDo You Want To Assign Seats By Alphabetical Order? (y/n)\n");

    // Allow the user to type "y" or "n" to see the names sorted in alphabetical order
    String letter = inp.next();

      // start a if statement for the input "y" and sort the names using Arrays.sort();
      if (letter.equals("y")){
        Arrays.sort(names); // Use Arrays.sort() function

        // Use a for loop to print the names in alphabetical order
        for (int x = 0; x < numOfStudents; x++){
        System.out.println(names[x]+" Seat Location: "+seats[x]);
        }
        
        // Create a print statement
        System.out.println("\nExit The Program? (y/n)\n");
        
        // Allow the user to type out "y" or "n" to exit the program
        String enter3 = inp.next();

        // Use an if statement to break the program 
        if (enter3.equals("y")){
          break;
      }else{
        continue;
      }

        // if the user types "n" as they do not want to see the names in an alphabetical order, then the user can exit the program
        }else{
        System.out.println("\nExit The Program? (y/n)\n");
        String enter2 = inp.next();
        if (enter2.equals("y")){
          break;
        }else{
          continue;
        }
      }
    }
  }
}

You should post a new question for a completely new requirement. Your edited question does not have any relation with the original question; how would the existing answers be justified? — Arvind Kumar Avinash, Oct 26 '20 at 18:43
I will do that but since I have to hand this assignment in about 20 mins, I would have to wait 1hr 30 mins to post a new question. Thats why. Sorry about that — , Oct 26 '20 at 18:47

score 1 · Accepted Answer · answered Oct 26 '20 at 18:22

1

You need to put the whole code inside a loop as shown below:

String enter2;
do {
    // Clear the screen
    System.out.print("\033[H\033[2J");
    System.out.flush();

    // Create scanner object
    Scanner inp = new Scanner(System.in);

    // ...put here the remaining lines of code

    System.out.println("\nExit The Program?\n");
    enter2 = inp.next();
    if (enter2.equals("y")) {
        System.out.println("\nHave A Nice Day!\n");
        break;
    }
} while (enter2.equalsIgnoreCase("n"));

answered Oct 26 '20 at 18:22

Arvind Kumar Avinash

71,965
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Hello Arvind, thanks for your Answer! But I included a while loop at the very beginning and broke the loop when the user typed y to exit the program and used Continue; when they wanted to stay in the program. I have another question: My sorting of the names alphabetically would not seem to work properly, could you take a look at my updated code? Thanks in advance! – Oct 26 '20 at 18:35

score 0 · Answer 2 · answered Oct 26 '20 at 18:29

Essentially this is not possible, but it is kind of possible.

Once your program has quit, there is no way it can still do something, because it does not run anymore. But you can initiate a new program instance right before the initial program instance ends. You do so by executing an OS command. To execute a command you can use e.g. the ProcessBuilder.

Here is an example what such code will look like:

How can I restart a Java application?

If you do not want to restart the whole program, but merely rerun your routine, you can follow the advice by @Arvind.

Arrays.sort() not functioning properly in java

2 Answers2