Question

i need to make a java program to play Yahtzee. it needs to use arrays. can you help me?

Answer 1

Description

• Ask the user how many dice the he/she wants to roll
• create an array of Die objects of the specified size
• Program then repeatedly roll all the dice until a Yahtzee is rolled occurs when all the dice have the same face value.
• Report how many rolls it took to obtain the Yahtzee.
• Program asks the user the option to run it again.

Program

import java.util.*;

public class Main {

public static void main(String[] args) {
Scanner keyboard = new Scanner (System.in); //create an object and reading input from the user
introduction(); //calling the introduction method
boolean runAgain = true; // declaring runAgain to true
while (runAgain){ // while statement runs until runagain is false
boolean rolledYahtzee = false; // declaring rolledYahtzee to false
int numRolls = 0; // initializing num of rolls as 0
Die [] dieArray = dieArray(keyboard); // creating an object diearray
while(!rolledYahtzee){ // while statement runs until rolledYahtzee is true
dieArray = rollDice (dieArray);
numRolls++;// incrementing num of rolls
printDots(numRolls);
rolledYahtzee = checkForYahtzee(dieArray, numRolls);// calling the method checkForYahtzee
}
printResults (numRolls, dieArray); // calling print method to print the results
runAgain = runAgain(keyboard);
}
}

public static void introduction(){ // introduction method
System.out.println("This program will");
}

public static Die [] dieArray(Scanner keyboard){ // method to check weather the given number is postive or not
int numDice = getInt(keyboard, "How many dice do you want to throw? ");
while (numDice <= 0){
System.out.println("Sorry, you must enter a positive number.");
numDice = getInt(keyboard, "How many dice do you want to throw? ");
}
Die [] dieArray = new Die [numDice];
return dieArray;
}

public static int getInt (Scanner keyboard, String prompt){ // method to check weather the given number is integer or a string
System.out.print(prompt);
while (!keyboard.hasNextInt()){
keyboard.next();
System.out.println("Sorry, you must enter an integer.");
System.out.print(prompt);
}
return keyboard.nextInt();
}

public static Die [] rollDice(Die [] dieArray){
for (int i = 0; i < dieArray.length; i++){
dieArray[i] = new Die ();
dieArray[i].roll();
dieArray[i].faceValue = dieArray[i].getValue();
}
return dieArray;
}

public static void printDots(int numRolls){
System.out.print(".");
if ((numRolls%50) == 0){
System.out.println();
}
}

public static boolean checkForYahtzee(Die[] dieArray, int numRolls) {
for(int i = 0; i < dieArray.length; i++) {
for(int j = i+1; j < dieArray.length; j++) {
if(dieArray[i].getValue() != dieArray[j].getValue()) {
return false;
}
}
}
return true;
}

public static void printResults (int numRolls, Die[] dieArray){
System.out.println();
System.out.println("Yahtzee!!");
System.out.print("After " + numRolls + " rolls, I finally rolled ");
System.out.println(dieArray.length + " " + dieArray[0].getValue() + "'s");
System.out.println();   
}

public static boolean runAgain (Scanner keyboard){
System.out.print("Do you want to run another experiment? (y|n)): ");
String answer = keyboard.next().trim().toLowerCase();
keyboard.nextLine();
System.out.println();
return (answer.charAt(0) == 'y');
}
}
class Die {
int faceValue;
public void roll(){
faceValue = (int)(Math.random() * 6 + 1);
}

public int getValue(){
return faceValue;   
}

public String toString(){
return Integer.toString(faceValue);
}
}

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