Program Requirements: Write a Java program that will 1. Ask the user to type in

Question

Program Requirements: Write a Java program that will 1. Ask the user to type in a sentence, using a JOptionPane.showInputDialog(). 2. The program will examine each letter in the string and count how many time the upper-case letter 'E' appears, and how many times the lower-case letter 'e' appears. The key here is to use the charAt method in class String. 3. Using a JOptionPane.showMessageDialog(), tell the user how many upper and lower case e's were in the string. 4. Repeat this process until the user types the word "Stop". (Check out the method equalsIgnoreCase in class String to cover all upper/lower case possibilities of the word "STOP".

Explanation / Answer

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

import javax.swing.JOptionPane;

public class StringUpperLowerFindings {

   public static void main(String[] args) {
       JOptionPane.showMessageDialog (null, "Please type your own words to find the count of Upper and Lower letters!", "Message", JOptionPane.INFORMATION_MESSAGE);
       JOptionPane.showMessageDialog (null, "To stop this process. Please type STOP / stop", "Message", JOptionPane.INFORMATION_MESSAGE);
      
       String sentence;
       do {
           System.out.println(" Please enter the input string :");
           //Reading input from user
           Scanner in = new Scanner(System.in);
           sentence = in.nextLine();
           if (!sentence.equalsIgnoreCase("stop")) {
               //To find number of upper and lower latters
               findUpperLowerLetters(sentence);
           }
       } while (!sentence.equalsIgnoreCase("STOP"));
       JOptionPane.showMessageDialog (null, "Thank You!", "Message", JOptionPane.INFORMATION_MESSAGE);      
   }
  
   private static void findUpperLowerLetters(String sentence) {
       //HashMap to store the each charater
       HashMap<Character, Integer> characterhashtable = new HashMap<Character, Integer>();
       int i, length;
       Character c;
  
       length = sentence.length(); // Scan string and build hash table
       for (i = 0; i < length; i++) {
           c = sentence.charAt(i);
           //If character id Caps
           if (characterhashtable.containsKey(c) && Character.isUpperCase(c)) {
               characterhashtable.put(c, characterhashtable.get(c) + 1);
               //if character is lower
           } else if (characterhashtable.containsKey(c) && Character.isLowerCase(c)) {
               characterhashtable.put(c, characterhashtable.get(c) + 1);
               //Add when letter appeared first time
           } else {
               characterhashtable.put(c, 1);
           }
       }
      
       String[] message = new String[characterhashtable.size()];
      
       // Create output message String
       Set set = characterhashtable.entrySet();
       Iterator iterator = set.iterator();
       int j=0;
       while (iterator.hasNext()) {
           Map.Entry mentry = (Map.Entry) iterator.next();
           message[j++] = mentry.getKey() + " appears " + mentry.getValue()+" times";
       }
       // Message box with Output
       JOptionPane.showMessageDialog(null, message, "Message",
               JOptionPane.INFORMATION_MESSAGE);
   }

}

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