Question

In this problem, you’ll play a simple rock, paper, scissors
game. First, you’ll ask the user to pick rock, paper, or
scissors.

Then, you’ll have the computer randomly choose one of the
options.

After that, print out the winner! You should keep playing the game until the user hits enter.

Note: You’ll need to implement a method called
String getWinner(String user, String computer). Luckily,
you just wrote that in an earlier program!

Here is a sample run of the program.

Enter your choice (rock, paper, or scissors):rock
User: rock
Computer: paper
Computer wins!
Enter your choice (rock, paper, or scissors):paper
User: paper
Computer: scissors
Computer wins!
Enter your choice (rock, paper, or scissors):scissors
User: scissors
Computer: paper
User wins!
Enter your choice (rock, paper, or scissors):rock
User: rock
Computer: rock
Tie
Enter your choice (rock, paper, or scissors):
Thanks for playing!

public class RockPaperScissors extends ConsoleProgram
{
private static final String USER_PLAYER = "User wins!";
private static final String COMPUTER_PLAYER = "Computer wins!";
private static final String TIE = "Tie";
  
private String getWinner(String user, String computer)
{

}
  
public void run()
{
  
}
}

Answer 1

Here is code:

ConsoleProgram.java:

import java.util.*;

public class ConsoleProgram {

private Scanner scanner;

public static void main(String[] args) {

// Assume the class name is passed in as the first argument.

if (args.length == 0) {

System.out.println("Please provide the name of the main class as an argument.");

return;

}

String mainClassName = args[0];

try {

Class mainClass = Class.forName(mainClassName);

Object obj = mainClass.newInstance();

ConsoleProgram program = (ConsoleProgram) obj;

program.run();

} catch (IllegalAccessException ex) {

System.out.println("Error in program. Make sure you extend ConsoleProgram");

} catch (InstantiationException ex) {

System.out.println("Error in program. Make sure you extend ConsoleProgram");

} catch (ClassNotFoundException ex) {

System.out.println("Error in program. Make sure you extend ConsoleProgram");

}

}

public void run() {

/* Overridden by subclass */

}

public ConsoleProgram() {

scanner = new Scanner(System.in);

}

public String readLine(String prompt) {

System.out.print(prompt);

return scanner.nextLine();

}

public double readDouble(String prompt) {

while (true) {

String input = readLine(prompt);

try {

double n = Double.valueOf(input).doubleValue();

return n;

} catch (NumberFormatException e) {

}

}

}

public int readInt(String prompt) {

while (true) {

String input = readLine(prompt);

try {

int n = Integer.parseInt(input);

return n;

} catch (NumberFormatException e) {

}

}

}

}

RockPaperScissors.java:

import java.util.Random;

public class RockPaperScissors extends ConsoleProgram {

private static final String USER_PLAYER = "User wins!";

private static final String COMPUTER_PLAYER = "Computer wins!";

private static final String TIE = "Tie";

private String getWinner(String user, String computer) {

String winner = "";

if (user.equalsIgnoreCase("scissors") && computer.equalsIgnoreCase("paper"))

winner = USER_PLAYER;

else if (user.equalsIgnoreCase("paper") && computer.equalsIgnoreCase("rock"))

winner = USER_PLAYER;

else if (user.equalsIgnoreCase("rock") && computer.equalsIgnoreCase("scissors"))

winner = USER_PLAYER;

else if (user.equalsIgnoreCase("rock") && computer.equalsIgnoreCase("rock"))

winner = TIE;

else if (user.equalsIgnoreCase("scissors") && computer.equalsIgnoreCase("scissors"))

winner = TIE;

else if (user.equalsIgnoreCase("paper") && computer.equalsIgnoreCase("paper"))

winner = TIE;

else

winner = COMPUTER_PLAYER;

return winner;

}

public void run() {

String choice, compChoice = "";

while (true) {

choice = readLine("Enter your choice (rock, paper, or scissors): ");

if (choice.length() == 0) {

break;

}

Random r = new Random();

int i = r.nextInt(3);

if (i == 0)

compChoice = "rock";

else if (i == 1)

compChoice = "paper";

else if (i == 2)

compChoice = "scissors";

System.out.println("User: " + choice);

System.out.println("Computer: " + compChoice);

System.out.println(getWinner(choice, compChoice));

}

System.out.println("Thanks for playing!");

}

}

Output:

Enter your choice (rock, paper, or scissors): rock User: rock Computer: paper Computer wins! Enter your choice (rock, paper, or scissors): paper User: paper Computer: paper Tie Enter your choice (rock, paper, or scissors): scissors User: scissors Computer: rock Computer wins! Enter your choice (rock, paper, or scissors): rock User: rock Computer: rock Tie Enter your choice (rock, paper, or scissors): Thanks for playing!