Develop Reference

How to fix a variable from a class not being subtracted in a method?

The gist of this assignment is that there are two players who take a stick out of a pile. I made a class that has the number of sticks available. There is a method that is called to remove sticks. However when I try to remove sticks the number of sticks doesn't change. Therefore the game not being able to end because there are still sticks "left".
I've tried using int sticks to be subtracted. The total amount of sticks changes but only in the method in which they are subtracted. The number of sticks don't change in the main method.
I decided to make use classes as I saw on this site that that is how this issue can be fixed. I've had no success with it.
So I made a class that has the amount of sticks so now the number of sticks is the same for each method. The same issue persists. One that changes the number of sticks in the getSticksRemove() method but not main() or getSticksLeft().
//Main Class
public class Main {
//Method to remove sticks which considers different scenarios.
public static int getSticksRemove(int sticks) {
sticks = StickPile.getValue(StickPile.value);
Scanner input = new Scanner(System.in);
print ("How many sticks to remove?(1-3)");
int x = input.nextInt();
if( x>=1 && x<=3) {
sticks -= x;
}else if(sticks < 3 && x ==2 ) {
print("Not enough sticks left.");
getSticksRemove(sticks);
}else if (x>3) {
sticks -=3;
}else { `enter code here`
sticks-=1;
}
print(sticks);
return sticks;
}
//Main method
public static void main(String [] args) {
StickPile stickPile = new StickPile();
int turnP1 = 0;
int turnP2 = 0;
int sticks = 0;
print("How many sticks are there initially? (1-100)");
StickPile.setValue();
sticks = StickPile.getValue(StickPile.value);
//This is the loop that determines when to stop the game
while(sticks != 0) {
System.out.print("Player 1: ");
getSticksRemove(sticks);
getSticksLeft(sticks);
turnP1++;
System.out.print("Player 2: ");
getSticksRemove(sticks);
getSticksLeft(sticks);
turnP2++;
}
if(turnP1 % 2 == 0 && turnP2 % 2 == 1) {
System.out.println("P2 Loses");
}else {
System.out.println("P1 Loses");
}
}
}
// This StickPile class is the one I made to store the number of sticks.
public class StickPile {
static Scanner input = new Scanner(System.in);
public static int value;
public static void setValue() {
value = input.nextInt();
}
public static int getValue(int x) {
x = value;
System.out.println(x);
return x;
}
I expect to enter a number of sticks to remove from the pile. Ex. PileAmount: 20--> Remove: 12--> PileAmount: 8.
However, I get Ex. PileAmoun: 20 --> Remove: 5--> PileAmount: 20,

You're ignoring the return of getSticksRemove. You can't reassign the parameter to effect the number outside of the function.
Just use the return value:
sticks = getSticksRemove(sticks)
Make that change in both places.

How to exit a loop based on what user pressed?

I am making a simple average grade calculator. Basically takes in users mark and the percentage of that module and displays the average percentage. The program does work but it has a few glitches which happens in the while loop.
The while loop should end as soon as the user enters any value under -1 but it continues on for a few times and then exits the while loop. Also, it first lets the user enter a number to ensure to start the while loop and then the text 'Enter Mark' comes up which makes the user enter their marks again. Im trying to make the while loop automatically start but dont know how too.
import java.util.ArrayList;
import java.util.Scanner;
public class percentage {
static ArrayList<Double> marks = new ArrayList<>();
static ArrayList<Double> percentage = new ArrayList<>();
static Scanner input = new Scanner(System.in);
static void addingToMarks(double currentmark) {
marks.add(currentmark);
}
public static void main(String[] args) {
System.out
.println("Type in the number of marks you got \n"
+ "in the module. And then type the percentage weight of it.\n"
);
double exitLoop = input.nextDouble();
while (exitLoop > -1) {
System.out.println("Type in your marks");
marks.add(input.nextDouble());
System.out
.println("Type in the weighted percentage of the module: ");
percentage.add(input.nextDouble());
exitLoop = input.nextDouble();
}
System.out.println(percentage);
System.out.println(marks);
System.out.println("Your average percent for the module is: "
+ gradeCalculate());
}
static double gradeCalculate() {
double totalaverageweight = 0;
for (int x = 0; x < marks.size(); x++) {
totalaverageweight += ((marks.get(x) / 100) * percentage.get(x));
}
return totalaverageweight;
}
}

I think a do... while loop will work in this case since the test condition will happen at the end of the loop
do{
////your code goes here
}while(exitLoop!=-1);

Calling local variables in other static methods?

I am supposed to write a program that selects a random number between user given constraints, and asks the user to input guesses as to what this number is. The program gives feedback to the user as to whether or not the number is higher or lower than the user's guesses. The number of guesses, the number of games, the total guesses used throughout all of the games, and the lowest number of guesses used in one game are recorded.
These results are printed. The functions that responsible for running the game (playGame()) and the functions responsible for printing these results (getGameResults()) must be in two separate methods.
My problem is, I am not sure how to get the local variables that are modified throughout the course of the method playGame() to the getGameResults() method.
getGameResults() is intended to be called in another method, continuePlayTest(), which tests the user's input to determine whether or not they wish to continue playing the game, so I don't think that calling getGameResults() will work, otherwise this test will not work either. Unless I call continuePlayTest() in playGame(), but continuePlayTest() calls playGame() in its code so that would complicate things.
We can use ONLY the concepts that we've learned. We cannot use any concepts ahead.
So far, we've learned how to use static methods, for loops, while loops, if/else statements and variables. Global variables are bad style, so they cannot be used.
CODE:
public class Guess {
public static int MAXIMUM = 100;
public static void main(String[] args) {
boolean whileTest = false;
gameIntroduction();
Scanner console = new Scanner(System.in);
playGame(console);
}
// Prints the instructions for the game.
public static void gameIntroduction() {
System.out.println("This process allows you to play a guessing game.");
System.out.println("I will think of a number between 1 and");
System.out.println(MAXIMUM + " and will allow you to guess until");
System.out.println("you get it. For each guess, I will tell you");
System.out.println("whether the right answer is higher or lower");
System.out.println("than your guess.");
System.out.println();
}
//Takes the user's input and compares it to a randomly selected number.
public static void playGame(Scanner console) {
int guesses = 0;
boolean playTest = false;
boolean gameTest = false;
int lastGameGuesses = guesses;
int numberGuess = 0;
int totalGuesses = 0;
int bestGame = 0;
int games = 0;
guesses = 0;
games++;
System.out.println("I'm thinking of a number between 1 and " + MAXIMUM + "...");
Random number = new Random();
int randomNumber = number.nextInt(MAXIMUM) + 1;
while (!(gameTest)){
System.out.print("Your guess? ");
numberGuess = console.nextInt();
guesses++;
if (randomNumber < numberGuess){
System.out.println("It's lower.");
} else if (randomNumber > numberGuess){
System.out.println("It's higher.");
} else {
gameTest = true;
}
bestGame = guesses;
if (guesses < lastGameGuesses) {
bestGame = guesses;
}
}
System.out.println("You got it right in " + guesses + " guesses");
totalGuesses += guesses;
continueTest(playTest, console, games, totalGuesses, guesses, bestGame);
}
public static void continueTest(boolean test, Scanner console, int games, int totalGuesses, int guesses, int bestGame) {
while (!(test)){
System.out.print("Do you want to play again? ");
String inputTest = (console.next()).toUpperCase();
if (inputTest.contains("Y")){
playGame(console);
} else if (inputTest.contains("N")){
test = true;
}
}
getGameResults(games, totalGuesses, guesses, bestGame);
}
// Prints the results of the game, in terms of the total number
// of games, total guesses, average guesses per game and best game.
public static void getGameResults(int games, int totalGuesses, int guesses, int bestGame) {
System.out.println("Overall results:");
System.out.println("\ttotal games = " + games);
System.out.println("\ttotal guesses = " + totalGuesses);
System.out.println("\tguesses/games = " + ((double)Math.round(guesses/games) * 100)/100);
System.out.println("\tbest game = " + bestGame);
}
}

If you cannot use "global" variables, I guess your only option is passing parameters when calling the method. If you don't know how to declare and use methods with parameters, I don't know another answer.
EDIT/ADD
After you specified your question, circumstances and posted your code I got a working solution including comments.
public class Guess {
public static int MAXIMUM = 100;
public static void main(String[] args) {
boolean play = true; // true while we want to play, gets false when we quit
int totalGuesses = 0; // how many guesses at all
int bestGame = Integer.MAX_VALUE; // the best games gets the maximum value. so every game would be better than this
int totalGames = 0; // how many games played in total
Scanner console = new Scanner(System.in); // our scanner which we pass
gameIntroduction(); // show the instructions
while (play) { // while we want to play
int lastGame = playGame(console); // run playGame(console) which returns the guesses needed in that round
totalGames++; // We played a game, so we increase our counter
if (lastGame < bestGame) bestGame = lastGame; // if we needed less guesses last round than in our best game we have a new bestgame
totalGuesses += lastGame; // our last guesses are added to totalGuesses (totalGuesses += lastGame equals totalGuesses + totalGuesses + lastGame)
play = checkPlayNextGame(console); // play saves if we want to play another round or not, whats "calculated" and returned by checkPlayNextGame(console)
}
getGameResults(totalGames, totalGuesses, bestGame); // print our final results when we are done
}
// Prints the instructions for the game.
public static void gameIntroduction() {
System.out.println("This process allows you to play a guessing game.");
System.out.println("I will think of a number between 1 and");
System.out.println(MAXIMUM + " and will allow you to guess until");
System.out.println("you get it. For each guess, I will tell you");
System.out.println("whether the right answer is higher or lower");
System.out.println("than your guess.");
System.out.println();
}
// Takes the user's input and compares it to a randomly selected number.
public static int playGame(Scanner console) {
int guesses = 0; // how many guesses we needed
int guess = 0; // make it zero, so it cant be automatic correct
System.out.println("I'm thinking of a number between 1 and " + MAXIMUM + "...");
int randomNumber = (int) (Math.random() * MAXIMUM + 1); // make our random number. we don't need the Random class with its object for that task
while (guess != randomNumber) { // while the guess isnt the random number we ask for new guesses
System.out.print("Your guess? ");
guess = console.nextInt(); // read the guess
guesses++; // increase guesses
// check if the guess is lower or higher than the number
if (randomNumber < guess)
System.out.println("It's lower.");
else if (randomNumber > guess)
System.out.println("It's higher.");
}
System.out.println("You got it right in " + guesses + " guesses"); // Say how much guesses we needed
return guesses; // this round is over, we return the number of guesses needed
}
public static boolean checkPlayNextGame(Scanner console) {
// check if we want to play another round
System.out.print("Do you want to play again? ");
String input = (console.next()).toUpperCase(); // read the input
if (input.contains("Y")) return true; // if the input contains Y return true: we want play another round (hint: don't use contains. use equals("yes") for example)
else return false; // otherwise return false: we finished and dont want to play another round
}
// Prints the results of the game, in terms of the total number
// of games, total guesses, average guesses per game and best game.
public static void getGameResults(int totalGames, int totalGuesses, int bestGame) {
// here you passed the total guesses twice. that isnt necessary.
System.out.println("Overall results:");
System.out.println("\ttotal games = " + totalGames);
System.out.println("\ttotal guesses = " + totalGuesses);
System.out.println("\tguesses/games = " + ((double) (totalGuesses) / (double) (totalGames))); // cast the numbers to double to get a double result. not the best way, but it works :D
System.out.println("\tbest game = " + bestGame);
}
}
Hope I could help.

Is it a problem passing the variables between functions? ex:
public static void getGameResults(int games, int totalGuesses, int guesses, int bestGame) {
// implementation
}
Another option, assuming this is all in one class, is using private static memeber variables. They aren't global. Then again, they might be considered 'global' by your teacher for this assignment.

Given that you've only learnt how to use static methods, your only option is to pass the information from function to function via its arguments.

Dice rolling program, but I need to transfer input data from a different class

I'm trying to create a program that will roll 2 different die, that could either be automatically 6 sided or custom sided as decided by the user. As of right now I've gotten this far and need help figuring out how to get anything to happen from the roll() method, I've tried running it and it won't give me the random int it should.
Any ideas?
import java.util.*;
import java.lang.*;
public class RollOfTheDice
{
public static void main(String[] args)
{ Die firstDie, secondDie, face;
firstDie = new Die();
secondDie = new Die();
face = new Die();
face.getSides();
firstDie.roll();
secondDie.roll();
System.out.println("First die roll results:.");
}
}
class Die
{
int numberOfSides; //field value
public Die() //constructor
{ numberOfSides = 6;
}
public int getSides()//get method
{ Scanner inputDevice = new Scanner (System.in);
System.out.println("If looking for a custom sided die, please enter number of sides now:");
numberOfSides = inputDevice.nextInt();
return numberOfSides;
}
public void setSides(int Sides) //setmethod
{
numberOfSides = Sides;
}
public int roll()
{
//return a random-generated integer value between 1 and amount of sides
int rollResult = ((int)(Math.random() * 100)% numberOfSides + 1);
return rollResult;
}
}

Since an answer has already been accepted, I figured I'd give a few pointers;
public int getSides()//get method
{ Scanner inputDevice = new Scanner (System.in);
System.out.println("If looking for a custom sided die, please enter number of sides now:");
numberOfSides = inputDevice.nextInt();
return numberOfSides;
}
I recommend not doing IO during getSides() which then has a side-effect of setting the number of sides in your die.
instead, have the main method run the "askForSides" method (which contains the scanner). and then pass this argument into a setSides() method.
secondly, I recommend that instead of your current constructor which sets the sides to a fixed 6 you replace it with:
public Die() //constructor
{
numberOfSides = 6;
}
public Die(int sides) {
this.numberOfSides = sides;
}
Even better (well, I like it anyway) is:
public Die() //constructor
{
this(6);
}
public Die(int sides) {
this.numberOfSides = sides;
}
this way only 1 constructor actually sets the sides, the other simply supplies a default. this makes refactoring easier in the long run.
if you have a constructor that takes sides as an argument, you can use that instead of the setSides method :)

Firstly, you do not actually println your roll result ever.
So to get that basic output, you can change the last 3 lines of your main() method to the following:
int firstRoll = firstDie.roll();
int secondRoll = secondDie.roll();
System.out.println("First die roll results:" + firstRoll);
System.out.println("Second die roll results:" + secondRoll);
This should at least get you to show the two dice rolls.

You did not simply forget to print out the actual value?
int first = firstDie.roll();
System.out.println("First die roll results: " + first);

You are calling roll, but not doing anything with the value that it returns.

Numberguessing class and client

I am trying to code a number guessing class and client.
The issue/problems I am having with this class/client is that my number guess either ends up too high or too low and in top of that it loops the number twice when it should once.
Number generated from 0 to 100. Wanna take a guess(enter 0 to give up)
Let's take a guess:
50
40
Your guess is too low
What possible change can I make to improve the overall loop or change.
Here is my code for anyone that wants to look at it.
import java.util.Random;
public class NumberGuess
{
private Random generator;
private int Number;
int intGuess= (1 + (int)(Math.random()*100));
int numGuess=0;
boolean isGuessCorrect=false;
public NumberGuess(){
}
int numguess;
public int guess(int guessIn){
int numguess=guessIn;
if(numguess>intGuess){
return 1;
}else if(isGuessCorrect){
return 0;
}else{
return -1;
}
}
public int getNumberofGuesses(){
return numGuess;
}
public boolean gameIsComplete(){
if(isGuessCorrect){
return true;
}else{
return false;
}
}
public void reset(){
intGuess=(1 + (int)(Math.random()*100));
numGuess=0;
isGuessCorrect=false;
}
}
Client class
import java.util.Scanner;
public class NumberGuessclient{
public static void main(String[] args){
NumberGuess game1=new NumberGuess();
Scanner scan = new Scanner(System.in);
int quit=1;
while(quit != 0) {
System.out.println("Number generated from 0 to 100. Wanna take a guess(enter 0 to give up)");
System.out.println("Let's take a guess: ");
int guess1= scan.nextInt();
while((guess1 != 0)||(!game1.gameIsComplete())) {
guess1 = scan.nextInt();
if (game1.guess(guess1)==1){
System.out.println("Your guess is too high");
}
else if(game1.guess(guess1)==-1) {
System.out.println("Your guess is too low");
}
else { System.out.println("guessed in " + game1.getNumberofGuesses() + " tries");
}
}
System.out.println("Enter 1 for new game, 0 to quit: ");
quit = scan.nextInt();
if(quit==1){
game1.reset();
}
}
}
}
source code for more ELABORATION if not clarified above.
NumberGuess Class:
The NumberGuess class will facilitate a number guessing game. The constructor should generate a random number, saving the number in a private class field. The class should also define a method which accepts a "guess", compares the "guess" to the randomly generated number, and returns one of the following:
• -1 the guess was less than the secret number
• 0 the guess matched the secret number
• 1 the guess was higher than the secret number
Determine whether other methods, constructors or otherwise, would be useful for this class.
The Java API defines a Random class for generating random numbers. The class can be reviewed in the API or in your textbook beginning on page 250. Consider limiting the range of the random number. For instance, a number between 0 and 100.
Client Application:
The client application allows the end-user to play the number guessing game. Below is a sample run. Your application does not need to match.
I'm thinking of a number between 0 and 100. Can you guess it?
Take a guess: 50
Your guess is too high
Another guess? (Y or N): y
Take a guess: 25
Your guess is too high
Another guess? (Y or N): y
Take a guess: 10
Your guess is too low
Another guess? (Y or N): y
Take a guess: 15
Your guess is too low
Another guess? (Y or N): y
Take a guess: 18
Your guess is too low
Another guess? (Y or N): y
Take a guess: 20
Congratulations! You correctly guessed the secret number in 6 tries.

There are quite a bit of things that you can change, for instance:
There's no need to call game1.guess(guess1) more than once every loop.
The completion method is quite long...
You should call scan.nextInt() before entering the while loop...
I'm assumming the last output was manually generated, because you never increment numguess
The guess(int) method doesn't work...
I'm not usually one to do homework... but (I'm having a good day...!):
import java.util.Random;
import java.util.Scanner;
public class NumberGuessclient {
private static final String[] ANS = {
"Your guess is too low\n",
"guessed in %d tries\n",
"Your guess is too high\n"
};
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
while (true) {
NumberGuess game = new NumberGuess();
System.out.println("Number generated from 0 to 100. Wanna take a guess(enter 0 to give up)");
System.out.println("Let's take a guess: ");
while (!game.isGameComplete()) {
System.out.format(ANS[game.guess(scan.nextInt())+1], game.getNumberofGuesses());
}
System.out.println("Enter 1 for new game, 0 to quit: ");
if (scan.nextInt() != 1) {
System.out.println("Bye!");
System.exit(0);
}
}
}
}
class NumberGuess {
private static final Random RAND_GENERATOR = new Random(System.nanoTime());
int intGuess = RAND_GENERATOR.nextInt(101);
int numGuess = 0;
boolean isGuessCorrect = false;
public int guess(int guessIn) {
numGuess++;
if (guessIn > intGuess) {
return 1;
} else if (guessIn == intGuess) {
isGuessCorrect = true;
return 0;
} else {
return -1;
}
}
public int getNumberofGuesses() {
return numGuess;
}
public boolean isGameComplete() {
return isGuessCorrect;
}
}
Now one comment: as I recall the "fun" of this game was that you should always "guess" the number in at the very most 10 tries, you could implement that...