Question

What to submit: your answers to exercises 1, 3, and 4 and separate the codes to each question.

1. Using your solution to question 3 of Lab Practice 2, modify it to create a class that contains a static method; the method takes a string as a parameter and returns a boolean value indicating whether the parameter string has repeated characters in it or not. That is, return true if there is at least one character which appears more than once in the string. The string should be input by the user.

==============================================================================================

codes using in question 3 of Lab Practice 2

package week02;

import java.util.Scanner;

public class Q3 {

   

                static public void main (String[] args)

    {

       Scanner scanner = new Scanner(System.in);

       System.out.println("Enter a string : ");

       String word = scanner.next();

       boolean repeatChar= false;

       for(int i =0; i<word.length();i++)

       {

                   char letter = word.charAt(i);

                                   

       for (int j=i+1; j<word.length(); j++)

       {        

                   char otherletter = word.charAt(j);

                   if(otherletter==letter)

           {

                                   repeatChar=true;

                                   break;  

                   }             

       }

       }

      

       if (repeatChar)

       {

                   System.out.println("There are repeated characters in it");

        }

      

                else

       {

                System.out.println("There are not repeated characters in it");

                }

    }

}

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2. The GUI program SimplApp.java is available from Topic 7 lecture slides. Copy the code and make a project; get the program to work. Without needing to understand everything the code does, you should at least understand the working of the constructor:

public SimpleApp(String windowTitle) { ... }

3. Copy and rename SimplApp.java; then modify it to create a GUI program that accepts a String from the user in a TextField and reports whether or not there are repeated characters in it. Thus your program is a client of the class which you created in question 1 above.

N.B. most of the modification needs to occur in the constructor and the actionPerformed() methods. So you should spend time working out exactly what these two methods are doing, so that you can make the necessary modifications.

4. This exercise extends exercise 1 from Lab Practice 5. Write a method that takes an integer array as its parameter and sorts the contents of the array in ascending order using the Insertion Sort algorithm (see Topic 6 lecture notes for the algorithm). Call this method (created in exercise 1 of Lab Practice 5) after the original array and other stats have been displayed. Once the array has been sorted by your method, display its contents to the screen in the same manner as the original array was displayed.

5. The GUI program BinarySearch.java is available from Topic 7 lecture slides. Copy the code and make a project; get the program to work. You should attempt to understand the operations of the Binary Search algorithm.

Answer 1

Answer:

I have written the program based on your requirements.

The below code works perfectly and it has no-errror.

You just simply Compile and Run the below program.

I have also attached the Output Screen-shot that I got by running the below program.

Output:

C:\Users\Public>javac Q3.java C:\Users\Public>java 23

X Find Repeat Char il Enter a String : aa CHECK

х Message i There are repeated characters in it OK

***********************************************************************************************************************************

Code:

Q3.java:

import java.io.*;
import java.util.*;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class Q3{

static public boolean repeatChar(String word)
{

boolean repeatChar= false;

for(int i =0; i<word.length();i++)
{
char letter = word.charAt(i);

for (int j=i+1; j<word.length(); j++)
{
char otherletter = word.charAt(j);

if(otherletter==letter)
{
repeatChar=true;
return true;
           }   
   }
}
return false;
}

static public void main (String[] args)

{
                  
                   JFrame frame=new JFrame("Find Repeat Char");
                   frame.setSize(300,300);
                  
                   JLabel l1=new JLabel("Enter a String : ");
                   l1.setBounds(80,50,100,30);
                  
                   JTextField f1=new JTextField();
                   f1.setBounds(75,100,100,30);
                  
                  
                   JButton button=new JButton("CHECK");
                   button.setBounds(75,150,100,30);
                  
                   frame.add(l1);
                   frame.add(f1);
                   frame.add(button);
                  
                   button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
  
           String temp=f1.getText();
              
               if(temp.equals(""))
               {
                   JOptionPane.showMessageDialog(frame,"TextField Should not be Empty !!!","Warning",JOptionPane.WARNING_MESSAGE);
               }
               else
               {
                   if(repeatChar(temp))
                   {
                       JOptionPane.showMessageDialog(frame,"There are repeated characters in it");
                   }
                   else
                   {
                       JOptionPane.showMessageDialog(frame,"There are not repeated characters in it");
                   }
                      
               }
                  
              
}
});
  
  

               frame.setLayout(null);
frame.setVisible(true);

}

}