Develop Reference

Problem with keeping score with a while loop (Java)

I am in an intro to the java class, and for one of my assignments, I have to use a loop (for or while) to keep track of scores between myself and the computer.
Here is the exact word for word instructions from my professor:
Write a program that does this: You (as a programmer) are the dealer.
pick a random number for yourself (between 0 - 100). Ask the user to input a random number (between 0 - 100) Whoever is closer to 21 wins the game.
(part 2) -Loop (keeping a counter) rite the same program and keep it going so that it keeps playing (dealing hands and saying who wins) until the user enters 21 at which point you print out some stats and say goodbye. For example, your goodbye might look like this:
Number of rounds played: 5
Dealer won: 3
Player won:2
you're 2 for 5.
Now I have written the code and played around it for hours and hours, and cannot make it work with a loop. I've tried while, do while, and for. I have looked everywhere on the internet for similar examples but cannot make a loop work in my program whatsoever. If anyone has any suggestions I would sure appreciate the feedback.
my code:
import java.util.*;
class asd {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Welcome Valued player, take your guess!");
int min = 0;
int max = 100;
int input;
int c = 21;
int count = 0;
int userscore = 0;
int dealerscore = 0;
int gamesplayed = 0;
Random rand = new Random();
int r = rand.nextInt(max - min) + min;
input = sc.nextInt();
System.out.println("computer's number:" + r);
if (Math.abs(input - c) <= Math.abs(r - c)) {
System.out.println("the winner is the user!" + input);
dealerscore++;
gamesplayed++;
} else {
System.out.println("the winner is the computer!" + r);
userscore++;
gamesplayed++;
}
if (input == c) {
System.out.println("thank you for playing. you won.");
}
if (r == c) {
System.out.println("Thank you for playing:" + userscore);
System.out.println(userscore);
}
if (input == 0) {
System.out.println("Number of hands played:" + gamesplayed);
System.out.println("Dealer won:" + dealerscore);
System.out.println("User won:" + userscore);
}
while (input != c && r != c)
gamesplayed++;
}
// TODO code application logic here
}
Everything works fine, but I can't get the loop to work anywhere here.

You need a while loop that contains your game logic. The condition should just check if the input != c.
Then inside the loop, keep asking the user for input. Also, you mixed up userscore and dealerscore when adding the score.
Then at the end, once you come out of the loop, you can print the scores/stats.
Please read the comments below:
import java.util.*;
public class MyClass {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Welcome Valued player, take your guess!: ");
int min = 0;
int max = 100;
int input;
int c = 21;
int count = 0;
int userscore = 0;
int dealerscore = 0;
int gamesplayed = 0;
Random rand = new Random();
int r = rand.nextInt(max - min) + min;
input = sc.nextInt();
/*
This loop runs the game until the user enters 21
*/
while (input != c) {
System.out.println("Computer's number:" + r);
if (Math.abs(input - c) <= Math.abs(r - c)) {
System.out.println("The winner is the user! " + input);
userscore++; //You mixed up userscore and dealerscore
} else {
System.out.println("The winner is the computer! " + r);
dealerscore++; //You mixed up userscore and dealerscore
}
/*
User needs to keep entering guesses
*/
System.out.println();
System.out.println("Enter another guess: ");
r = rand.nextInt(max - min) + min;
input = sc.nextInt();
}
/*
You don't need any conditions since the games have already ended
But it should be outside and after the loop
*/
System.out.println("Number of hands played:" + gamesplayed);
System.out.println("Dealer won:" + dealerscore);
System.out.println("User won:" + userscore);
}
}

Change the loop with
while (input != c && r != c){
gamesplayed++;
System.out.println("Games played: " + gamesplayed );
}
you will see it is working. I would format the code better to debug it easier and always use the brackets.

Try this. Just refer to the code for explanations.
import java.util.Random;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Welcome Valued player, take your guess!");
System.out.println("");
int min = 0;
int max = 100;
int input;
int c = 21;
int userscore = 0;
int dealerscore = 0;
int gamesplayed = 1;
Random rand = new Random();
while (true) { // so that the game will keep playing
System.out.println("----------------- ROUND " + gamesplayed + " -----------------");
int r = rand.nextInt(max - min) + min; // computer's choice
while (true) { // so that it will keep asking the user in case the user enters an invalid input
try {
System.out.print("Enter a random number! :");
input = Integer.parseInt(sc.nextLine());
break;
} catch (Exception e) {
System.out.println("Invalid input!");
}
}
System.out.println("The computer's random number is " + r);
// checking for the rounds winner
if (Math.abs(input - c) <= Math.abs(r - c)) {
System.out.println("The winner is the user!");
userscore++;
} else {
System.out.println("The winner is the computer!");
dealerscore++;
}
if (input == c) { // checking for ending the game
System.out.println("================ GAME STATS ================");
System.out.println("Thank you for playing.");
System.out.println("Number of hands played: " + gamesplayed);
System.out.println("Dealer score: " + dealerscore);
System.out.println("User score: " + userscore);
System.out.println("You are " + userscore + " out of " + gamesplayed + "!");
System.out.println("============================================");
sc.close();
break;
}
gamesplayed++; // increment games played
System.out.println("--------------------------------------------");
}
}
}

How to properly pass a variable?

Here is my code, this program is a simple number guessing game, in which the computer picks a random number between 1 and x (set within the program) and the user is to guess the number using feedback from the computer stating whether each guess is higher or lower than secret number.
The code consists of 4 methods, a main method in which several variables are declared after displaying instructions for playing. Then a while loop is setup to start a new game. 3 lines into the while loop, a method is called to start playing a new game, passing both the scanner/console and an integer called guesses (which is set to 0 each time this method is called).
This integer, guesses, increments by one each time the user makes a guess and should be returned at the end of the game method, but I cannot seem to figure out why it is not being returned. It needs to be returned so it can be passed to the results method to calculate the stats that will be displayed if the user decides not to play again.
Any help would be appreciated...
import java.util.*;
public class Guess {
public static void main(String[] Args) {
Scanner console = new Scanner(System.in);
Introduction(); //required
int games = 0;
int newGame = 1;
int guesses = 0;
int maxguesses = 0;
int totalguesses = 0;
while (newGame == 1) {
String userNewGame = "";
games = games + 1;
Game(guesses,console); //required
if (guesses > maxguesses) {
guesses = maxguesses;
}
totalguesses = totalguesses + guesses;
System.out.print("Do you want to play again? ");
userNewGame = console.next();
System.out.println();
char first = userNewGame.charAt(0);
if ( first == 'Y' || first == 'y') {
newGame = 1;
}
else if ( first == 'N' || first == 'n') {
newGame = 0;
}
}
Results(games,totalguesses,maxguesses); //required
}
public static void Introduction() {
System.out.println("This program allows you to play a guessing game.");
System.out.println("I will think of a number between 1 and 100");
System.out.println("and will allow you to guess until you get it.");
System.out.println("For each guess, I will tell you whether the");
System.out.println("right answer is higher or lower than your guess.");
System.out.println();
}
public static int Game(int guesses, Scanner console) {
Random rand = new Random();
int range = 100; //Change this value to set the range the computer will require to guess ie. 100 is 1 to 100 inclusive, 5 is 1 to 5 inclusive, etc.
int number = rand.nextInt(range) + 1;
guesses = 0;
int guess = -1;
System.out.println("I'm thinking of a number...");
while (guess != number) {
System.out.print("Your guess? ");
guess = console.nextInt();
guesses = guesses + 1;
if (guess < number) {
System.out.println("higher");
}
if (guess > number) {
System.out.println("lower");
}
if (guess == number) {
System.out.println("You got it right in " + guesses + " guesses");
System.out.println();
}
}
return guesses;
}
public static void Results(int games,int totalguesses,int maxguesses) {
System.out.println("Overall results:");
System.out.println(" total games = " + games);
System.out.println(" total guesses = " + totalguesses);
System.out.println(" guesses/game = " + totalguesses / games);
System.out.println(" max guesses = " + maxguesses);
}
}

There's a handful of things going on here, and all of them kind of build on one another.
You're not capturing the result of the value you get back from Game.
You're doing some very strange things with your variables, which reduces readability.
You're going to run into issues with your Scanner down the line, as you loop through this program.
Let's start with the low-hanging fruit. Game returns an int, but it's not being assigned anywhere. Ideally, it should be assigned to the value of guesses.
guesses = Game(guesses,console); //required
...except it doesn't really make sense to pass guesses in when:
we're reassigning it in main (don't worry, the Game method will have its own copy of guesses anyway since Java is pass by value)
you explicitly assign it to 0 inside of Game anyway
So instead, you want to remove that as an argument to your method.
guesses = Game(console);
And inside of Game, you can define your own guesses variable.
public static int Game(Scanner console) {
Random rand = new Random();
int range = 100; //Change this value to set the range the computer will require to guess ie. 100 is 1 to 100 inclusive, 5 is 1 to 5 inclusive, etc.
int number = rand.nextInt(range) + 1;
int guesses = 0;
int guess = -1;
System.out.println("I'm thinking of a number...");
while (guess != number) {
System.out.print("Your guess? ");
guess = console.nextInt();
guesses = guesses + 1;
if (guess < number) {
System.out.println("higher");
}
if (guess > number) {
System.out.println("lower");
}
if (guess == number) {
System.out.println("You got it right in " + guesses + " guesses");
System.out.println();
}
}
return guesses;
}
The last obvious issue I can see is one where you're using next(), but you're not quite clearing the buffer for a Scanner.
userNewGame = console.next();
// and inside of Game()
guess = console.nextInt();
This is a surprisingly common Scanner problem, and it's easy enough to work around.
userNewGame = console.next();
console.nextLine();
// and inside of Game()
guess = console.nextInt();
console.nextLine();
Alternatively, you could use nextLine instead and not deal with next() since they both return String. The difference being that next() doesn't consume the newline character generated by Return/Enter, and nextLine() does.

Instead of just calling the Guesses method, you should use the returned value to update your variable, like so:
guesses = Game(guesses,console); //required
If you want the maxguesses to hold the max amount of guesses (among all the games), then you should update your logic after the Game method is called like so,
if (guesses > maxguesses) {
maxguesses = guesses; // not guesses = maxguesses
}
This is the whole code I am posting which works fine I think. Check it out:
import java.util.*;
public class Guess {
public static void main(String[] Args) {
Scanner console = new Scanner(System.in);
Introduction(); //required
int games = 0;
int newGame = 1;
int guesses = 0;
int maxguesses = 0;
int totalguesses = 0;
while (newGame == 1) {
String userNewGame = "";
games = games + 1;
guesses = Game(guesses,console); //required
if (guesses > maxguesses) {
maxguesses = guesses;
}
totalguesses = totalguesses + guesses;
System.out.print("Do you want to play again? ");
userNewGame = console.next();
System.out.println();
char first = userNewGame.charAt(0);
if ( first == 'Y' || first == 'y') {
newGame = 1;
}
else if ( first == 'N' || first == 'n') {
newGame = 0;
}
}
Results(games,totalguesses,maxguesses); //required
}
public static void Introduction() {
System.out.println("This program allows you to play a guessing game.");
System.out.println("I will think of a number between 1 and 100");
System.out.println("and will allow you to guess until you get it.");
System.out.println("For each guess, I will tell you whether the");
System.out.println("right answer is higher or lower than your guess.");
System.out.println();
}
public static int Game(int guesses, Scanner console) {
Random rand = new Random();
int range = 100; //Change this value to set the range the computer will require to guess ie. 100 is 1 to 100 inclusive, 5 is 1 to 5 inclusive, etc.
int number = rand.nextInt(range) + 1;
guesses = 0;
int guess = -1;
System.out.println("I'm thinking of a number...");
while (guess != number) {
System.out.print("Your guess? ");
guess = console.nextInt();
guesses = guesses + 1;
if (guess < number) {
System.out.println("higher");
}
if (guess > number) {
System.out.println("lower");
}
if (guess == number) {
System.out.println("You got it right in " + guesses + " guesses");
System.out.println();
}
}
return guesses;
}
public static void Results(int games,int totalguesses,int maxguesses) {
System.out.println("Overall results:");
System.out.println(" total games = " + games);
System.out.println(" total guesses = " + totalguesses);
System.out.println(" guesses/game = " + totalguesses / games);
System.out.println(" max guesses = " + maxguesses);
}
}
Sample output:
This program allows you to play a guessing game.
I will think of a number between 1 and 100
and will allow you to guess until you get it.
For each guess, I will tell you whether the
right answer is higher or lower than your guess.
I'm thinking of a number...
Your guess? 10
higher
Your guess? 50
lower
Your guess? 40
lower
Your guess? 30
lower
Your guess? 20
lower
Your guess? 15
You got it right in 6 guesses
Do you want to play again? y
I'm thinking of a number...
Your guess? 50
higher
Your guess? 80
higher
Your guess? 90
lower
Your guess? 85
You got it right in 4 guesses
Do you want to play again? n
Overall results:
total games = 2
total guesses = 10
guesses/game = 5
max guesses = 6

Having trouble w/ returning and passing values; "counting"

Our task was to create a guessing game, where the computer would generate a number and the user was prompted to guess. We were to create a method to play only one game, and then create a while loop in the main to make the game playable again. In the end, we need to show statistics. I'm having trouble with showing the "best game." That is a game where the amount of guesses is the least.
Here is the code:
import java.util.Random;
import java.util.Scanner;
public class GuessingGame {
public static final int MAX = 100;
// This is the main. Here we can see a do/while loop
// and a few variables that were created to compliment it.
public static void main(String[] args) {
Random rand = new Random();
Scanner console = new Scanner(System.in);
intro();
String s = "";
int totalGames = 0;
int totalGuess = 0;
do {
totalGuess = game(console);
System.out.print("Do you want to play again? ");
s = console.next();
totalGames++;
} while (s.equals("y") || s.equals("Y") || s.equals("Yes") ||
s.equals("yes") || s.equals("Yes"));
totalGuess = totalGuess;
statistics(totalGames, totalGuess);
}
// This method prints out the intro.
public static void intro() {
System.out.println("This program allows you to play a guessing
game.");
System.out.println("I will think of a number between 1 and");
System.out.println(MAX + " 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.\n ");
}
// This method plays the game only once. It's later used in the main.
// Returns the
// number of guesses for one game.
public static int game(Scanner console) {
Random rand = new Random();
int random = rand.nextInt(MAX) + 1;
System.out.println("I'm thinking of a number between 1 and " + MAX + "
... (it's " + random + " )");
System.out.print("Your guess? > ");
int guess = console.nextInt();
int count = 0;
do {
if ((random - guess) > 0) {
System.out.println("It's higher.");
System.out.print("Your guess? > ");
guess = console.nextInt();
count++;
}
else if ((random - guess) < 0) {
System.out.println("It's lower.");
System.out.print("Your guess? > ");
guess = console.nextInt();
count++;
}
else if (random == guess) {
count++;
}
} while (random != guess);
if (count == 1) {
System.out.println("You got it right on the first guess!!");
}
else {
System.out.println("You got it right in " + count + " guesses.");
}
return count;
}
// This method prints out the statistics.
public static void statistics(int x, int y) {
System.out.println("total games = " + x);
System.out.println("total guesses = " + (y));
System.out.println("guesses/game = ");
System.out.println("best game = ");
}
}

Have a look when totalGuess is assigned:
public static void main(String[] args) {
Random rand = new Random();
Scanner console = new Scanner(System.in);
intro();
String s = "";
int totalGames = 0;
int totalGuess = 0;
// ^ Initialized to zero
do {
totalGuess = game(console);
// ^ Assigned (not added) to the return value from game.
// Did you mean: totalGuess += game(console); ?
System.out.print("Do you want to play again? ");
s = console.next();
totalGames++;
} while (s.equals("y") || s.equals("Y") || s.equals("Yes") ||
s.equals("yes") || s.equals("Yes"));
totalGuess = totalGuess;
// ^ Assigned to itself. No action.
statistics(totalGames, totalGuess);
}

Issue with Java Guessing Game

I'm working on this guessing game for school. I've realized that at some point I deleted my while loop for the user's guess equalling the computer's random number and it has messed up the results of my program. I thought that I could just add a nested while loop, but that hasn't worked. I've been trying to figure this out for hours.
Any ideas how to add something like while (guess == number) to my code and keep it working?
/*
Programming Assignment #3: Guess
Peter Harmazinski
Week 8
Guessing Game
*/
import java.util.*;
public class Guess {
public static final int RANGE = 100;
public static void main(String[] args) {
Scanner console = new Scanner(System.in);
boolean again = true;
double guessesDividedByGames = 0;
int maxGuesses = 0;
int numGames = 0;
int numGuesses = 1;
int totalGuesses = 0;
Random rand = new Random();
int number = rand.nextInt(RANGE) + 1;
int guessTracker = 0;
while(again) {
getInstructions();
int guess = getGuess(console);
numGuesses = getHigherLower(guess, number, console);
totalGuesses += numGuesses;
again = playAgain(numGuesses, console);
numGames++;
if (numGuesses > maxGuesses) {
maxGuesses = numGuesses;
}
}
guessesDividedByGames = (double)totalGuesses / numGames;
getResults(numGames, totalGuesses, guessesDividedByGames, maxGuesses);
}
//Prints instructions for user
public static void getInstructions() {
System.out.println("This program allows you to play a guessing game");
System.out.println("I will think of a number between 1 and " + RANGE);
System.out.println("and will allow you to guess until you get it.");
System.out.println("For each guess, I will tell you whether the");
System.out.println("right answer is higher or lower than your guess");
System.out.println("");
}
//Allows the user to play again if first letter of input is "y" or "Y"
public static boolean playAgain(int guessesNum, Scanner console) {
boolean anotherTime = false;
System.out.println("You got it right in " + guessesNum + " guesses.");
System.out.println("");
System.out.print("Do you want to play again? ");
String repeat = console.next();
String[] yesOrNo = repeat.split("");
System.out.println("");
if (yesOrNo[0].equals("y") || yesOrNo[0].equals("Y")) {
anotherTime = true;
}
return anotherTime;
}
//Outputs the results if the user doesn't play again
public static void getResults(int gamesTotal, int guessesTotal, double guessesDividedByGames, int guessesMax) {
System.out.println("Overall results:");
System.out.println("\ttotal games\t= " + gamesTotal);
System.out.println("\ttotal guesses\t= " + guessesTotal);
System.out.println("\tguesses/game\t= " + guessesDividedByGames);
System.out.println("\tmax guesses\t= " + guessesMax);
}
//Tells the user whether the random number is higher or lower
//and then returns the number of guesses
public static int getHigherLower(int guess, int randomNumber, Scanner console) {
int guessIncreaser = 1;
while (guess > randomNumber) {
System.out.println("lower");
guess = getGuess(console);
guessIncreaser++;
}
while (guess < randomNumber) {
System.out.println("higher");
guess = getGuess(console);
guessIncreaser++;
}
return guessIncreaser;
}
//Asks the user to guess the random number
//then returns the guess
public static int getGuess(Scanner console) {
System.out.println("I'm thinking of a number...");
System.out.print("Your Guess? ");
int playerGuess = console.nextInt();
while (playerGuess < 1 || playerGuess > RANGE) {
System.out.println("Out of range, please try again.");
System.out.print("Your Guess? ");
playerGuess = console.nextInt();
}
return playerGuess;
}
}

The problem appears to be your getHigherLower method, specifically these two while blocks:
while (guess > randomNumber) {
System.out.println("lower");
guess = getGuess(console);
guessIncreaser++;
}
while (guess < randomNumber) {
System.out.println("higher");
guess = getGuess(console);
guessIncreaser++;
}
If the user guessed a number lower than randomNumber, then higher, both while blocks would be escaped. Instead, what you want is this:
while (guess != randomNumber) {
if (guess > randomNumber) {
System.out.println("lower");
}
else {
System.out.println("higher");
}
guess = getGuess(console);
guessIncreaser++;
}

What you need is one big while loop not two little ones
while (guess != randomNumber) {
if (guess > randomNumber) {
System.out.println("lower");
} else {
System.out.println("higher");
}
guess = getGuess(console);
guessIncreaser++;
}

First off, I'm hesitant to just give you the answer in code since this is for a school project and we learn by challenging ourselves and actualizing solutions. But I'm willing to point you in the right direction.
1. getHigherLower()
As others have pointed out, your two while loops are set up to cause errors. For instance, if I first guess too low, and then too high, your method mistakenly tells me I guessed correctly. This is a big problem!
Random number = 63
Guess 1 = 34 (lower)
Guess 2 = 100 (higher)
Actually your program tells me my guess of "100" when the number is "63" is correct!
// 1st conditional check: 34 !> 63, so skips first while loop
while (guess > randomNumber) {
guess = getGuess(console);
}
// 1st conditional check: 34 < 63, so enters second while loop
// 2nd conditional check: 100 !< 63, so skips second while loop
while (guess < randomNumber) {
// guess now becomes 100, goes back to top of while loop to check condition again
guess = getGuess(console);
}
// returns and exits method here (program wrongly thinks user has guessed correctly!)
Note that you can do a
System.out.println("random number: " + number);
to test that you're actually guessing the random number correctly. You might look into some JUnit testing as well.
James Ko seems to have a good feel for a better method implementation.
2. playAgain()
You use an if statement to check if the first index in an array of strings equals "y" or "Y" but your program never continues. Why is this?
if (yesOrNo[?].equals("y") {
anotherTime = true;
}
You should consider whether user input is really being placed at the first index or not?
Hint: loop through the "yesOrNo" array and print out each index to see where the user input is being placed in the array.
for (int i = 0; i < yesOrNo.length; i++) {
System.out.println("String at index " + i + ": " + yesOrNo[i]);
}
Good luck and remember that testing is your friend!

Creating 1 decimal place

So I am more or less completely done with this code that runs a guessing game. At the end it prints the total results for all games played. This includes total games, total guesses, avg guesses/game and the best score. I have it all worked out except i need the avg guesses/game to show 1 decimal place but the System.out.printf("Guesses/game = %.1f") isn't working and idk why
import java.util.*; //so I can use scanner
public class GuessingGame {
public static void main(String[] args) {
Random rand = new Random ();
int max = 100;
Scanner input = new Scanner(System.in);
int guess;
boolean play = true;
int totalGames = 0;
int totalGuesses = 0;
int bestGame = Integer.MAX_VALUE;
System.out.println("Can you guess the word?");
System.out.println("I am sure you cannot guess!");
System.out.println("Go ahead and try!");
System.out.println();
while (play) { //repeats until user enters a statement besides y when asked to play again
System.out.println("I'm thinking of a number between 1 and " + max + "...");
int numberToGuess = rand.nextInt(max) + 1;
int numberOfTries = 0;
boolean win = false;
while (!win) {
System.out.print("Your guess? ");
guess = input.nextInt();
numberOfTries++;
if (guess == numberToGuess) {
win = true;
} else if (guess > numberToGuess) {
System.out.println("It's lower.");
} else if (guess < numberToGuess) {
System.out.println("It's higher.");
}
input.nextLine();
}
if (numberOfTries == 1) {
System.out.println("You got it right in " + numberOfTries + " guess!");
} else {
System.out.println("You got it right in " + numberOfTries + " guesses!");
}
totalGames++;
totalGuesses+= numberOfTries;
System.out.print("Do you want to play again? ");
String answer = input.nextLine();
char firstLetter = answer.charAt(0);
if (firstLetter == 'y' || firstLetter == 'Y') {
play = true;
} else {
play = false;
bestGame = Math.min(bestGame, numberOfTries);
}
System.out.println();
}
System.out.println("Overall results:");
System.out.println("Total games = " + totalGames);
System.out.println("Total guesses = " + totalGuesses);
System.out.printf("Guesses/game = ", totalGuesses/totalGames);
System.out.println("Best game = " + bestGame);
}
}

both totalGuesses and totalGames are integers, so when you divide them you get an integer, whereas %f needs a floating point number.
Instead cast one to a floating point number for floating point division:
totalGuesses/(double)totalGames

Try a decimal formatter if for some reason you're simply getting the wrong output:
DecimalFormat formatter = new DecimalFormat("#.#");
System.out.println(formatter.format(avgGuesses)); //or whatever your var name is