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.

Random number (1-100) picking loop program | Understanding methods

what I am looking to do is create a program that will randomly pick an integer between 1 and 100. Then, ask the user to guess it. Loop until they do, and after each incorrect guess tell them if they are too high or too low. I want to use two different methods to validate their input. One to test whether it is a valid int, the other to test the range (1-100). This second will require another parameter for the high range value.
The problems I am having:
1. I do not understand why I have to enter a number multiple times before my while (guess != a) { is triggered.
Example from console :
I am thinking of a number from 1 to 100 ... guess what it is ?6
I am thinking of a number from 1 to 100 ... guess what it is ?6
I am thinking of a number from 1 to 100 ... guess what it is ?6
6
higher!
2. how could I use my check methods and have them pertain to my while guess loop?
Example from console again:
`I am thinking of a number from 1 to 100 ... guess what it is? 10001
I am thinking of a number from 1 to 100 ... guess what it is? 10001
Error! Must be less than 100
I am thinking of a number from 1 to 100 ... guess what it is? 10001
100
lower!
10001
lower!`
{What I have full written currently}
package labbs;
import java.util.Scanner;
public class Lab12 {
public static double getDoubleGreaterThan(double low, Scanner input, String prompt) {
double num;
num = getDouble(input,prompt);
if(num <= low)
System.out.println("Error! Must be greater than 1");
num = getDouble(input,prompt);
if (num > 100)
System.out.println("Error! Must be less than 100");
num = getDouble(input,prompt);
return num;
}
public static double getDouble(Scanner input, String prompt) {
boolean OK;
double val=0;
do {
System.out.print(prompt);
OK = true;
try {
val = input.nextDouble();
}
catch(Exception e) {
OK = false;
System.out.println("Error! Invalid input. Must be a double value");
input.next();
}
}while(! OK);
return val;
}
public static void main(String args[]) {
Scanner keyboard = new Scanner(System.in);
double output, letscheck;
int count=0, guess=0;
int a=1 + (int) (Math.random() * 99);
letscheck = getDoubleGreaterThan(-0.9, keyboard,"I am thinking of a number from 1 to 100"
+ " ... guess what it is ?");
while (guess != a) {
guess = keyboard.nextInt();
count++;
if (guess > a) {
System.out.println("lower!");
} else if (guess < a) {
System.out.println("higher!");
}
}
System.out.println("Congratulations. You guessed the number with "
+ count + " tries!");
}
}

1. Query: You have just missed bracket in getDoubleGreaterThan()method as after if statement block always working not on the basis of input so change your code like below:
public static double getDoubleGreaterThan(double low, Scanner input, String prompt) {
double num;
num = getDouble(input,prompt);
if(num <= low){
System.out.println("Error! Must be greater than 1");
num = getDouble(input,prompt);
}
if (num > 100){
System.out.println("Error! Must be less than 100");
num = getDouble(input,prompt);
}
return num;
}

Java / Creating hi/low game using multiple methods, stuck at returning no. of guesses

I'm creating a high/low guessing game as part of a study assignment, and the part im stuck at is getting the amount of guesses returned to the main method. We have specifically been told that the main method has to print the number of guesses, while the method "playGame" actually does the playing.
There's more to the code, a method called giveReponse that checks if the number is correct or too high/low, but it works as intended. I get "Cannot find symbol" when trying to print how many guesses it took to complete the game.
If it wasn't so important to print it in the main method I'd print the amount in the method playGame, but thats a no-go. What am I doing wrong?
The code looks like this:
public class HiLo {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Welcome to classic guessing game of high/low!");
String difficulty = scan.next();
if (difficulty.equals("easy")) {
playGame(10);
} else if (difficulty.equals("medium")) {
playGame(100);
} else if (difficulty.equals("hard")) {
playGame(1000);
}
System.out.println("You won in" + guesses + "attempts.");
}//EndsMain
public static int playGame(int maxNumber) {
Scanner scan = new Scanner(System.in);
int rannr = (int)(Math.random() * maxNumber) +1;
int answer = rannr;
int guess = 0;
int guesses = 0;
System.out.println("Game is starting...");
do {
guess = scan.nextInt();
guesses ++;
giveResponse(answer, guess);
if (answer == guess) {
break;
}
} while (answer != guess);
return guesses;
} //Ends playGame

Your method playGame( ) is returning a value but since is not assigned to no variable, those returns are getting lost...
additional to that it looks like the code is not complete:
this statement is not going to let you compile:
System.out.println("You won in" + guesses + "attempts.");
because the only guesses variable I see in there is scoped in the playGame method....
do instead something like:
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Welcome to classic guessing game of high/low!");
int guesses = 0;
String difficulty = scan.next();
if (difficulty.equals("easy")) {
guesses = playGame(10);
} else if (difficulty.equals("medium")) {
guesses = playGame(100);
} else if (difficulty.equals("hard")) {
guesses = playGame(1000);
}

The problem is at:
System.out.println("You won in" + guesses + "attempts.");
Since the variable guesses is not defined in the main method, the compiler doesn't know what you are referencing to with that symbol.
But since playGame() returns the number of guesses, I'd recommend something like this:
if (difficulty.equals("easy")) {
System.out.println("You won in" +playGame(10)+ "attempts.");
} else if (difficulty.equals("medium")) {
System.out.println("You won in" +playGame(100)+ "attempts.");
} else if (difficulty.equals("hard")) {
System.out.println("You won in" +playGame(1000)+ "attempts.");
}

Here's a solution that shows how easy it would be to restrict guesses. Not much extra effort or thought:
package games;
import java.util.Random;
import java.util.Scanner;
/**
* HiLo guessing game
* Created by Michael
* Creation date 4/9/2016.
* #link https://stackoverflow.com/questions/36522303/java-creating-hi-low-game-using-multiple-methods-stuck-at-returning-no-of-gu
*/
public class HiLo {
public static void main(String [] args) {
int maxValue = (args.length > 0) ? Integer.parseInt(args[0]) : 100;
int maxGuesses = (args.length > 1) ? Integer.parseInt(args[1]) : 5;
Scanner scanner = new Scanner(System.in);
String answer = "Y";
do {
play(scanner, maxValue, maxGuesses);
System.out.println("Play again? [Y/N]: ");
answer = scanner.next();
System.out.println(String.format("You answered %s; let's play again!", answer));
} while ("Y".equalsIgnoreCase(answer));
}
private static void play(Scanner scanner, int maxValue, int maxGuesses) {
int value = new Random().nextInt(maxValue) + 1;
int numGuesses = 0;
boolean match = false;
do {
System.out.println(String.format("Guess a value between 1 and %d: ", maxValue));
int guess = Integer.parseInt(scanner.next());
if (guess < value) {
System.out.println(String.format("Too low; guess again. (%d guesses left)", (maxGuesses-numGuesses-1)));
} else if (guess > value) {
System.out.println(String.format("Too high; guess again (%d guesses left)", (maxGuesses-numGuesses-1)));
} else {
match = true;
System.out.println(String.format("You got it right in %d guesses! ", numGuesses+1));
break;
}
} while (!match && ++numGuesses < maxGuesses);
if (!match) {
System.out.println(String.format("The correct answer was %d; you're only allowed %d guesses. Better luck next time!", value, maxGuesses));
}
}
}

Making a program with a range that can change during the course of the program (Java)

I am working on a project where you make a code that has the computer guess a random number, and then the user says if that number is higher or lower. Then the computer is supposed to change its parameters based on what the user says. For example if it guesses 33 and you say too low and it says 74 and it says too high, then the next number generated will be between 33 and 74. My problem is, I can make the range get higher with using the rFinder variable and such when UserAnswer=2 in the RepeatedGuess method. But, though trying many things, I can't get a range that is dynamic or that changes throughout the code. Am I approaching this completely the wrong way? Any suggestions would be helpful.
import java.util.Scanner;
import java.util.Random;
public class Proj72 {
private static int UserAnswer;
private static int maximum = 100;
private static int minimum = 0;
private static int rFinder;
private static Random generator = new Random();
private static Scanner reader = new Scanner(System.in);
private static int guess = generator.nextInt(100);
public static void main(String[] args) {
FirstGuess();
RepeatedGuesses();
Correct();
}
private static void FirstGuess() {
System.out.print(guess + ": Is this your number? Enter 1 For Yes or enter 2 for Too Low or enter 3 for Too High:");
}
private static void RepeatedGuesses() {
while (1 != UserAnswer) {
UserAnswer = reader.nextInt();
if (2 == UserAnswer) {
rFinder = (int)(generator.nextInt(100 - guess));
guess = rFinder + guess;
System.out.print(guess + ": Is this your number? Enter Yes or enter Higher or enter Lower:");
} else if (3 == UserAnswer)
break;
}
}
private static void Correct() {
if (1 == UserAnswer) {
System.out.print("I got it!");
}
}
}

Keep track of the range of values that the guess could be. Call these min and max. Min is equal to 0 and max is equal to 100 at the beginning.
Guess a random int between the min and max
After each guess:
if the number is above the guess, set the min to the guess
if the number is below the guess, set the max to the guess
To progress further, instead of choosing a random guess each time, guess the value in the middle of the min and max values, e.g. 50 for the first guess.
This is then a binary search with O(log(N)) worst and average time!

private static void RepeatedGuesses() {
while (1 != UserAnswer) {
UserAnswer = reader.nextInt();
if (2 == UserAnswer) {
rFinder = (int) (generator.nextInt(100 - guess));
guess = rFinder + guess;
System.out.print(guess + ": Is this your number? Enter Yes or enter Higher or enter Lower:");
} else if (3 == UserAnswer){
break;
}
//change it
FirstGuess();
UserAnswer = reader.nextInt();
}
}

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.