We Keep Coding

Throws Exception when trying to break loop because a condition has been met

I am trying to figure out why I cannot get the loop to break if either "n" is input for playAgain or when the total is below $10. If you see how I can break the loop to run the gameOver function without having an exception thrown that would be a great help. I have noted in the code below that I am having trouble with. I am unsure why this exception is being thrown. If you are able to find out how to break the loop when total is less than 10 or when playAgain is false please let me know!
import java.util.Random;
import java.util.Scanner;
public class GameOfCrapsTester {
static Scanner in = new Scanner(System.in);
static Random rand = new Random();
public static void main(String[] args) {
System.out.println("Welcome to the game of Craps");
System.out.println(" ");
System.out.println("The house has given you a starting balance of $500");
System.out.println("On each round, you will make a whole number wager.");
System.out.println("The minimum wager is $10, and the maximum wager is your remaining balance.");
System.out.println(" ");
System.out.println("You may keep playing until you decide to cash in, or");
System.out.println(" you can't cover the minimum wager.");
System.out.println("Good Luck!");
boolean win;
double wins = 0, numOfGames = 0;
int total = 500;
// Come out roll and set point value
int pointValue = 0;
boolean playAgain = true;
while (playAgain && total > 0)
{
System.out.println(" ");
System.out.println("Your balance is $" + total);
System.out.println(" ");
System.out.println("Place your bet: $");
// Get and check wager placed
int bet = in.nextInt();
while (bet > total || bet < 10)
{
if (bet < 10)
{
System.out.println("Bet must be larger than $10.");
}
System.out.println("I'm sorry, that's not a valid wager; please re-enter: ");
bet = in.nextInt();
}
int num = rollDice();
if ((num >= 4 && num <= 10 && num != 7) || num == 0)
{
pointValue = num;
System.out.println(" ");
System.out.println("Your point value is " + pointValue);
System.out.println(" ");
win = rollWithPoint(pointValue);
if (win)
{
total = wonGame(bet, total);
wins++;
numOfGames++;
System.out.println("Wins: " + wins + " Number of games: " + numOfGames);
}
else if (!win)
{
total = lostGame(bet, total);
numOfGames++;
System.out.println("Wins: " + wins + " Number of games: " + numOfGames);
}
}
else if (num == 7 || num == 11)
{
total = wonGame(bet, total);
wins++;
numOfGames++;
System.out.println("Wins: " + wins + " Number of games: " + numOfGames);
}
else
{
total = lostGame(bet, total);
numOfGames++;
System.out.println("Wins: " + wins + " Number of games: " + numOfGames);
}
if (total <= 9) // THIS IS WHERE I AM HAVING TROUBLE
{
break;
}
System.out.println("Keep playing (y/Y or n/N)? ");
in.nextLine();
String again = in.nextLine();
if (again.equalsIgnoreCase("y"))
{
playAgain = true;
}
else if (again.equalsIgnoreCase("n")) // THIS IS WHERE I AM HAVING TROUBLE
{
break;
}
else
{
System.out.println("Invalid character input, try again:");
again = in.nextLine();
}
}// end of loop
gameOver(wins, numOfGames);
} // END of main
public static int rollDice() {
int dice1, dice2, total;
dice1 = rand.nextInt(6) + 1;
dice2 = rand.nextInt(6) + 1;
total = dice1 + dice2;
System.out.print("Your roll: ");
System.out.print("Dice1: " + dice1);
System.out.print(", Dice2: " + dice2);
System.out.println("; Roll Value: " + total);
return total;
} // END of rollDice
public static boolean rollWithPoint(int point) {
int total = rollDice();
boolean winner = false;
while(total != 7 && winner == false)
{
total = rollDice();
if (total == point)
{
winner = true;
}
else
{
winner = false;
}
}
return winner;
} // END of rollWithPoint
public static int lostGame(int bet, int total) {
System.out.println("Oh, I'm sorry, you lost.");
System.out.println(" ");
total = total - bet;
System.out.println("Your current balance: $" + total);
System.out.println(" ");
return total;
} // END of lostGame
public static int wonGame(int bet, int total) {
System.out.println("A winner!");
System.out.println(" ");
total = total + bet;
System.out.println("Your current balance: $" + total);
System.out.println(" ");
return total;
} // END of wonGame
public static void gameOver(double win, double tot) {
double winPercent = (win / tot) * 100;
System.out.println(" ");
System.out.printf("Based on your play, the probability of winning is %.2%", winPercent);
System.out.println(" ");
System.out.println("Seems you lost your shirt; better luck next time.");
System.out.println("Have a nice day! Hope to see you soon!");
} // END of gameOver
} // END of GameOfCraps

There is no error when you change this (without using String.format()):
System.out.printf("Based on your play, the probability of winning is %.2%", winPercent);
To this:
System.out.println("Based on your play, the probability of winning is " + winPercent + "%.");
Example with a little bet (console):
Your balance is $11
Place your bet: $
10
Your roll: Dice1: 1, Dice2: 2; Roll Value: 3
Oh, I'm sorry, you lost.
Your current balance: $1
Wins: 0.0 Number of games: 2.0
Based on your play, the probability of winning is 0.0%.
Seems you lost your shirt; better luck next time.
Have a nice day! Hope to see you soon!
I cannot get the loop to break if either "n" is input for playAgain or
when the total is below $10.
It works fine too. If I put a bet below 10 it asks me to put another bit. What

ArrayList If Loop not working properly: JAVA

I have a program that asks the user their name etc. Then it asks how many times do you want the numbers to loop (so my program generates 3 random numbers between 7 and 13 and if it adds up to 31 they are the winner) and my issue is that I only want the last printed number to count towards if the player wins or looses, the other numbers are just for show or tease i guess. the problem is that regardless towards if the player wins or looses, the losing statement always prints out. Below is my entire code.
import java.util.InputMismatchException;
import java.util.Scanner;
import java.io.IOException;
import java.util.Random;
public class StringVariables {
public static void main(String[] args) throws NumberFormatException,
IOException {
// user inputs their name in this section
Scanner user_input = new Scanner(System.in);
//enter their first name
String first_name;
System.out.print("Enter Your First Name: ");
while
(!user_input.hasNext("[A-Za-z]+")) {
System.out.println("Please only enter alphabet characters. Try again.");
user_input.next();
}
first_name = user_input.next();
//enter their last name
String last_name;
System.out.print("Enter Your Last Name: ");
while
(!user_input.hasNext("[A-Za-z]+")) {
System.out.println("Please only enter alphabet characters. Try again.");
user_input.next();
}
last_name = user_input.next();
//full name printed together
String full_name;
full_name = first_name + " " + last_name;
System.out.println(full_name + " Is Now Playing");
// this is the shuffle portion as well as something to see if a number
int numShuffles = -1;
while (numShuffles < 0) {
System.out.println("How many times do you want the numbers shuffled? ");
try {
numShuffles = user_input.nextInt();
} catch (InputMismatchException inputException) {
System.out.print("Please enter a valid number. \n");
//this is the buffer that resets if the user types a letter instead of a number, or any other character
user_input.next();
}
}
// here is going to be the loop for shuffles
// we are now going to generate their random number and add a delay
// after completing their name fields
delay(3000);
System.out
.println(" You will be given " + numShuffles + " hand(s) of 3 random numbers between 7-13" );
delay(2000);
System.out
.println(" Then, the computer will add the random numbers and if it is equal to 31, you win!");
/*
* end of explanation of the game, next i will create a new screen with
* the user's name and numbers
*/
delay(4000);
// printing 25 blank lines
for (int i = 0; i < 25; i++)
System.out.println(" ");
System.out.println("User playing: " + full_name);
System.out.println("Number of times shuffled: " + numShuffles);
System.out.println("Your lucky numbers are...");
// random number generator
Random random = new Random();
while (true) {
// the shuffle loop
Arraylist numberStore = new Arraylist();
boolean isWinner = false;
for (int i = 0; i < numShuffles; i++) {
int num1 = 7 + random.nextInt(7);
int num2 = 7 + random.nextInt(7);
int num3 = 7 + random.nextInt(7);
System.out.println(num1 + " + " + num2 + " + " + num3 + " = " + (num1 + num2 + num3));
numberStore.add(num1 + num2 + num3);
int lastNumber = (numberStore.size() - 1);
if (lastNumber == 31) {
isWinner = true;
System.out.println("Congratulations !! You are the Lucky Winner !!!!");
break;
//if you loose every shuffle
}
}
if (!isWinner) {
System.out.println("Better Luck Next Time");
}
// play again prompt
System.out
.println(" Do you want to play again? (If you do enter y or yes) \n To exit press any other key ");
String input = user_input.next();
if (!"y".equalsIgnoreCase(input) && !"yes".equalsIgnoreCase(input)) {
break;
}
}
// if pressed y or yes the program will run again with the same number of shuffles entered from before
user_input.close();
}
// delay field
public static void delay(int millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException exp) {
// delay field
}
}
}

int lastNumber = (numberStore.size() - 1);
if (lastNumber == 31) {
you probably want something like
int lastNumber = numberStore.get(numberStore.size() - 1);
if (lastNumber == 31) {
to verify that is the error try to change that line to
int lastNumber = num1 + num2 + num3;
Edit based on further messages:
Looks like what you really want is this:
for (int i = 0; i < numShuffles; i++) {
int num1 = 7 + random.nextInt(7);
int num2 = 7 + random.nextInt(7);
int num3 = 7 + random.nextInt(7);
System.out.println(num1 + " + " + num2 + " + " + num3 + " = " + (num1 + num2 + num3));
numberStore.add(num1 + num2 + num3);
int lastNumber = num1 + num2 + num3;
boolean lastShuffle = (i == (numShuffles - 1));
if (lastShuffle) {
if (lastNumber == 31) {
System.out.println("Congratulations !! You are the Lucky Winner !!!!");
} else {
System.out.println("Better Luck Next Time");
}
}
}
// play again prompt
System.out
.println(" Do you want to play again? (If you do enter y or yes) \n To exit press any other key ");
String input = user_input.next();
if (!"y".equalsIgnoreCase(input) && !"yes".equalsIgnoreCase(input)) {
break;
}
Just a general suggestion: avoid to use break if possible, it makes control flow hard to follow and is not a good programming practice.

Several points to make here. One, your code is quite messy and hard to read. It's helpful when you're asking for help (and in general anyway) to properly indent your code. This is good practice and if you do other languages like Python can help you out a lot. Also, why do a check for !isWinner? Scrap the isWinner variable altogether and just check for the number equalling 31 and then have an else statement for the losing statement. Like this:
if (lastNumber == 31) {
System.out.println("Congratulations !! You are the Lucky Winner !!!!");
break;
//if you loose every shuffle
}
else {
System.out.println("Better Luck Next Time");
}
Also, take some steps to find the error. Print out each number as you get it, and use
int lastNumber = num1 + num2 + num3;
instead of
int lastNumber = (numberStore.size() - 1);
Also for anybody else compiling this, it's ArrayList and not Arraylist... just a little slip.

Sorry, I may have to say that your codes are a kind of mess up. a small factory with the solution you ask, hope it can be a little help to you
public static void main(String[] args) throws NumberFormatException,
IOException {
Scanner user_input = new Scanner(System.in);
String full_name = registeGamePlayer(user_input);
int numShuffles = initGame(user_input);
showTheGameInfo(full_name, numShuffles);
runningGame(user_input, numShuffles);
user_input.close();
}
/**
* #param user_input
* #param numShuffles
*/
private static void runningGame(Scanner user_input, int numShuffles) {
// random number generator
Random random = new Random();
while (true) {
// the shuffle loop
boolean isWinner = false;
for (int i = 0; i < numShuffles; i++) {
int num1 = 7 + random.nextInt(7);
int num2 = 7 + random.nextInt(7);
int num3 = 7 + random.nextInt(7);
int amount = num1 + num2 + num3;
System.out.printf("%d + %d + %d = %d \n", num1,num2,num3,amount);
if (amount == 31) {
isWinner = true;
System.out.println("Congratulations !! You are the Lucky Winner !!!!");
break;
// if you loose every shuffle
}
}
if (!isWinner) {
System.out.println("Better Luck Next Time");
}
// play again prompt
System.out.println(" Do you want to play again? (If you do enter y or yes) \n To exit press any other key ");
String input = user_input.next();
if (!"y".equalsIgnoreCase(input) && !"yes".equalsIgnoreCase(input)) {
break;
}
}
}
/**
* #param full_name
* #param numShuffles
*/
private static void showTheGameInfo(String full_name, int numShuffles) {
// printing 25 blank lines
for (int i = 0; i < 25; i++)
System.out.println(" ");
System.out.println("User playing: " + full_name);
System.out.println("Number of times shuffled: " + numShuffles);
System.out.println("Your lucky numbers are...");
}
// delay field
public static void delay(int millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException exp) {
// delay field
}
}
private static String registeGamePlayer(Scanner user_input){
String first_name;
System.out.print("Enter Your First Name: ");
while (!user_input.hasNext("[A-Za-z]+")) {
System.out
.println("Please only enter alphabet characters. Try again.");
user_input.next();
}
first_name = user_input.next();
// enter their last name
String last_name;
System.out.print("Enter Your Last Name: ");
while (!user_input.hasNext("[A-Za-z]+")) {
System.out
.println("Please only enter alphabet characters. Try again.");
user_input.next();
}
last_name = user_input.next();
// full name printed together
String full_name;
full_name = first_name + " " + last_name;
System.out.println(full_name + " Is Now Playing");
return full_name;
}
private static int initGame(Scanner user_input){
// this is the shuffle portion as well as something to see if a number
int numShuffles = -1;
while (numShuffles < 0) {
System.out.println("How many times do you want the numbers shuffled? ");
try {
numShuffles = user_input.nextInt();
} catch (InputMismatchException inputException) {
System.out.print("Please enter a valid number. \n");
// this is the buffer that resets if the user types a letter
// instead of a number, or any other character
user_input.next();
}
}
// here is going to be the loop for shuffles
// we are now going to generate their random number and add a delay
// after completing their name fields
delay(3000);
System.out.println(" You will be given " + numShuffles + " hand(s) of 3 random numbers between 7-13");
delay(2000);
System.out.println(" Then, the computer will add the random numbers and if it is equal to 31, you win!");
/*
* end of explanation of the game, next i will create a new screen with
* the user's name and numbers
*/
delay(4000);
return numShuffles;
}

How can i add replayability to this blackjack game?

import java.util.*;
import java.util.Scanner;
public class Assignment2 {
public static void main(String args[]){
Scanner stdin = new Scanner(System.in);
Random random = new Random();
int ran2 = (random.nextInt(10));
int ran1 = (random.nextInt(10));
int total = ran1 + ran2;
char exit = 'y';
System.out.println("First cards: " + ran1 + ", " + ran2);
System.out.println("Total: " + total);
while(exit != 'n' && total < 21){
System.out.println("Do you want another card? (y/n): ");
exit = stdin.next().charAt(0);
if (exit =='n'){
System.out.println("Would you like to play again? (y/n): ");
exit = stdin.next().charAt(0);
if(total > 21 || exit == 'n'){
break;
}
}
int next = random.nextInt(10);
System.out.println("Card: "+ next);
total = total + next;//adds
System.out.println("Total: "+ total);
if(total > 21){
System.out.println("Bust.");
break;
}
if(total == 21){
System.out.println("You win!");
break;
}
}
}
}
i got the game working and all, but if i wanted to play from the beginning to where you get your first cards, how would i do it? after you win or lose how would i make it restart the game? i've been trying to figure this out and still cant find out how do it

Wrap your code in another loop :)
Scanner stdin = new Scanner(System.in);
char exit = 'n';
while( exit != 'n' ) {
// your old code here
System.out.println("Play again ? (y/n):")
exit = stdin.next().charAt(0);
}

How to randomly position a variable within X + Y = Z operation and loop

I basically want to be able to loop an X + Y = Z equation until the user inputs something other than an integer, like the letter "A" and also when having any number make the loop stop displaying a message.
Also, I am confused on how to randomly position the "?" which the user must input the correct answer.
For example
System.out.println("What is: " + num1 + " + ? = " + answer);
So far:
I am positioning the "?" manually through the IF statements. Can this be done in a more efficient way?
public static void main(String[] args) {
Random rand = new Random();
Scanner input = new Scanner(System.in);
int num1, num2, number3, answer;
do {
num1= 1 + rand.nextInt(10);
num2= 1 + rand.nextInt(10);
answer= num1 + num2;
System.out.println("What is: " + num1 + " + ? = " + answer);
number3= input.nextInt();
if (number3 == num2)
System.out.println("That is correct");
else
System.out.println("That is wrong");
num1= 1 + rand.nextInt(10);
num2= 1 + rand.nextInt(10);
answer= num1 + num2;
System.out.println(num1 + " + ? = " + answer);
number3= input.nextInt();
} while(number3 !=0);
}

Here is one way to do it:
public static void main(String[] args) {
Random rand = new Random();
Scanner scanner = new Scanner(System.in);
int[] xyz = new int[3];
String[] display = new String[3];
int answer, position;
do {
xyz[0] = 1 + rand.nextInt(10);
xyz[1] = 1 + rand.nextInt(10);
xyz[2] = xyz[0] + xyz[1];
for (int i = 0; i < xyz.length; i++)
display[i] = String.valueOf(xyz[i]);
position = rand.nextInt(3);
display[position] = "?";
System.out.println("What is: " + display[0] + " + " + display[1] + " = " + display[2]);
do {
System.out.println("Please enter an integer or 'S' to stop");
String input = scanner.nextLine();
if (input.equals("S")) {
scanner.close();
System.out.println("Stopped");
return;
}
else if (input.matches("\\d+")) { // \\d+ means "a digit (0-9) once or more
answer = Integer.parseInt(input);
break;
}
} while (true);
if (answer == xyz[position])
System.out.println("That is correct");
else
System.out.println("That is wrong");
} while (true);
}
Notes:
I use an inner do-while loop to repeatedly check the input and ask the user for a valid input.
I use 2 arrays: one for storing the numbers and another for storing the display values.
I also added a stop condition since the outer loop is infinite. Always close the Scanner when you finish.
I randomly pick 1 of 3 positions for the "?".

Java entering test score validation

I am trying to output the amount of test scores between 5 and 35. I do get an invalid entry when the integer entered is below 5 or above 35, which is required. However, when I enter a number between 5 and 35, nothing happens. I get a blank line. The only way I can get "Enter Score" to show up is when I enter another number and press "Enter/Return". What am I doing wrong?
Here is my code:
============================
import java.text.NumberFormat;
import java.util.Scanner;
public class ValidatedTestScoreApp
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
String choice = "y";
while (!choice.equalsIgnoreCase("n"))
{
int scoreTotal = 0;
int scoreCount = 0;
int testScore = 0;
int maximumScore = 0;
int minimumScore = 100;
// get the number of scores to be entered
int amtTest = getIntWithinRange(sc,"Enter the number of test scores to be entered: ", 5, 35);
int numberOfEntries = sc.nextInt();
System.out.println();
sc.nextLine();
for (int i = 1; i <= numberOfEntries; i++)
{
int testScores = getIntWithinRange(sc, "Enter score " + i + ": ", 1, 100);
testScore = sc.nextInt();
// accumulate score count and score total
if (testScore <= 100)
{
scoreCount += 1;
scoreTotal += testScore;
maximumScore = Math.max(maximumScore, testScore);
minimumScore = Math.min(minimumScore, testScore);
}
else if (testScore != 999)
{
System.out.println("Invalid entry, not counted");
i--;
}
}
// calculate the average score
double averageScore = (double) scoreTotal / (double) scoreCount;
// display the results
NumberFormat number = NumberFormat.getNumberInstance();
number.setMaximumFractionDigits(1);
String message = "\n" +
"Score count: " + scoreCount + "\n"
+ "Score total: " + scoreTotal + "\n"
+ "Average score: " + number.format(averageScore) + "\n"
+ "Minimum score: " + minimumScore + "\n"
+ "Maximum score: " + maximumScore + "\n";
System.out.println(message);
// see if the user wants to enter more test scores
System.out.print("Enter more test scores? (y/n): ");
choice = sc.next();
System.out.println();
}
}
public static int getInt(Scanner sc, String prompt)
{
int i = 0;
boolean isValid = false;
while (isValid == false)
{
System.out.print(prompt);
if (sc.hasNextInt())
{
i = sc.nextInt();
isValid = true;
}
else
{
System.out.println("Error! Invalid integer value. Try again.");
}
sc.nextLine();
}
return i;
}
public static int getIntWithinRange(Scanner sc, String prompt,
int min, int max)
{
int i = 0;
boolean isValid = false;
while (isValid == false)
{
i = getInt(sc, prompt);
if (i <= min)
System.out.println(
"Error! Number must be greater than " + min + ".");
else if (i >= max)
System.out.println(
"Error! Number must be less than " + max + ".");
else
isValid = true;
}
return i;
}
}

The problem is that you are trying to read the values multiple times.
int testScores = getIntWithinRange(sc, "Enter score " + i + ": ", 1, 100);
testScore = sc.nextInt();
Here you already got the value from the getIntWithinRangeMethod, but on the next line you are reading it again.
Also what are the amtTest and testScores variables good for? I'm not sure what you are trying to accomplish, but I guess you need to do these two changes:
// get the number of scores to be entered
// int amtTest = getIntWithinRange(sc, "Enter the number of test scores to be entered: ", 5, 35);
// int numberOfEntries = sc.nextInt();
int numberOfEntries = getInt(sc, "Enter the number of test scores to be entered: ");
// System.out.println();
// sc.nextLine();
...
// int testScores = getIntWithinRange(sc, "Enter score " + i + ": ", 1, 100);
testScore = getIntWithinRange(sc, "Enter score " + i + ": ", 1, 100);
After this, the programs behaves fine and I get this:
Enter the number of test scores to be entered: 2
Enter score 1: 5
Enter score 2: 6
Score count: 2
Score total: 11
Average score: 5.5
Minimum score: 5
Maximum score: 6
Enter more test scores? (y/n):