Example: Toggle Case Using Character Methods in Java

// Toggle Case Using Character Methods
// No specific imports needed for basic Character operations within the same package.
// If using specific utilities like Scanner, import java.util.Scanner;
import java.util.Scanner; // Example import, not strictly needed for this program alone

public class Main {
    public static void main(String[] args) {
        // Step 1: Define the input string
        String inputString = "Hello World 123!";
        System.out.println("Original String: " + inputString);

        // Step 2: Initialize a StringBuilder to build the toggled string
        StringBuilder toggledStringBuilder = new StringBuilder();

        // Step 3: Iterate through each character of the input string
        for (char ch : inputString.toCharArray()) {
            // Step 4: Check if the character is an uppercase letter
            if (Character.isUpperCase(ch)) {
                // Step 5: Convert uppercase to lowercase and append
                toggledStringBuilder.append(Character.toLowerCase(ch));
            }
            // Step 6: Else, check if the character is a lowercase letter
            else if (Character.isLowerCase(ch)) {
                // Step 7: Convert lowercase to uppercase and append
                toggledStringBuilder.append(Character.toUpperCase(ch));
            }
            // Step 8: If not a letter, append the character as is
            else {
                toggledStringBuilder.append(ch);
            }
        }

        // Step 9: Convert StringBuilder to String and print the result
        String toggledString = toggledStringBuilder.toString();
        System.out.println("Toggled String: " + toggledString);

        // Example with user input (optional)
        // Scanner scanner = new Scanner(System.in);
        // System.out.print("\nEnter another string to toggle: ");
        // String userInput = scanner.nextLine();
        // StringBuilder userToggled = new StringBuilder();
        // for (char ch : userInput.toCharArray()) {
        //     if (Character.isUpperCase(ch)) {
        //         userToggled.append(Character.toLowerCase(ch));
        //     } else if (Character.isLowerCase(ch)) {
        //         userToggled.append(Character.toUpperCase(ch));
        //     } else {
        //         userToggled.append(ch);
        //     }
        // }
        // System.out.println("User Toggled String: " + userToggled.toString());
        // scanner.close();
    }
}