学习

Additional Practice · Jimmy Huang's Blog

java

import java.util.Scanner;

/**
 * This program demonstrates an infinite for-loop in Java.
 * It repeatedly prompts the user for input until the user types "exit".
 *
 * @author Jimmy
 * @version 1.0
 */
public class IndefiniteFor 
{
    // Constructors

    /**
     * No-argument constructor.
     */
    public IndefiniteFor() 
    {
    }

    // methods

    /**
     * The main method runs an infinite loop that accepts user input
     * and exits when the user types "exit" (case-insensitive).
     *
     * @param args Command-line arguments (not used).
     */
    public static void main(String[] args) 
    {
        Scanner scanner = new Scanner(System.in);

        for (;;) 
        {
            System.out.print("Please enter a number (or type 'exit' to quit): ");
            String input = scanner.nextLine();

            if (input.equalsIgnoreCase("exit")) 
            {
                System.out.println("Loop exited");
                break;
            }
            System.out.println("You entered: " + input);
        }
        scanner.close();
    }

    /**
     * Returns a string representation of the IndefiniteFor class.
     *
     * @return A description of what this class does.
     */
    @Override
    public String toString() 
    {
        return "This class runs an infinite loop that reads user input until 'exit' is entered.";
    }

}

java

/**
 * This program accepts a string input and prints it in reverse order.
 *
 * @author Jimmy
 * @version 1.0
 */
import java.util.Scanner;

public class ReverseString
{
    // Constructor
    public ReverseString()
    {
    }

    // Methods

    /**
     * The main program reads a single line of input and prints the reversed
     * string with each character's case flipped.
     *
     * @param args Command-line arguments (not used).
     */
    public static void main(String[] args)
    {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter a string to reverse with case flipped:");
        String input = scanner.nextLine();
        int length = input.length();
        char[] result = new char[length];

        for (int i = 0; i < length; i++)
        {
            char c = input.charAt(length - 1 - i);

            if (Character.isUpperCase(c))
            {
                result[i] = Character.toLowerCase(c);
            }
            else if (Character.isLowerCase(c))
            {
                result[i] = Character.toUpperCase(c);
            }
            else
            {
                result[i] = c;
            }
        }
        
        String reversed = new String(result);
        System.out.println(reversed);

        scanner.close();
    }

    /**
     * A toString method
     *
     */
    @Override
    public String toString()
    {
        return "This class reverses a string and flips the case" +
            "of each character.";
    }
}

学习

学习

学习

Additional Practice

Code challenge 1

Answer

Code challenge 2

Answer

本页目录

学习

Additional Practice

Code challenge 1

Answer

Code challenge 2

Answer

本页目录