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How to stop a while loop in java after inputting a specific string?

Im trying to stop a loop that takes integers after typing in the console "End", but i cant seem to find a way to do it.
Scanner scan = new Scanner(System.in);
int bottles = Integer.parseInt(scan.nextLine()) * 750;
int cnt = 1;
int platesTotal;
int potsTotal;
int nrPlates = 0;
int nrPots = 0;
while(true){
int plates = scan.nextInt();
platesTotal = plates * 5;
if(cnt%3==0) {
int pots = scan.nextInt();
nrPots = nrPots + pots;
nrPlates = nrPlates + pots;
potsTotal = pots * 15;
if (bottles < potsTotal + platesTotal) {
System.out.println("Not enough detergent, " + (potsTotal + platesTotal - bottles) + " ml. more necessary!");
break;
}
else
if(bottles >= potsTotal + platesTotal) {
String enough = scan.nextLine();
if (enough.equals("End")) {
if (bottles >= potsTotal + platesTotal) {
System.out.println("Detergent was enough!");
System.out.println(nrPlates + " dishes and " + nrPots + "pots were washed.");
System.out.printf("Leftover detergent %d ml.", bottles - potsTotal - platesTotal);
break;
}
}
}
}
cnt++;
}
after inputting the string ("End"), it needs to show me the total of dishes and pots, and how much detergent it has left, and if the required amount of detergent is more than the available amount, it needs to show me how much more is needed.

Try this String enough = scan.next(); instead of scan.nextLine();

I would suggest printing messages to console to confirm to the user you want input. Otherwise, it'll just show a blank window. I would also suggest you define a boolean variable to escape the while loop while switching your enough to .next rather than .nextLine. This way, you redefine your boolean as false to break the while loop while also getting the output you desire to control your program output a bit more. This compiled with all entries of 1:
package com.climatedev.test;
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
System.out.println("How many bottles?");
Scanner scan = new Scanner(System.in);
int bottles = scan.nextInt() * 750;
int cnt = 1;
int platesTotal;
int potsTotal;
int nrPlates = 0;
int nrPots = 0;
boolean run = true;
while(run){
System.out.println("How many plates?");
int plates = scan.nextInt();
platesTotal = plates * 5;
if(cnt%3==0) {
int pots = scan.nextInt();
nrPots = nrPots + pots;
nrPlates = nrPlates + pots;
potsTotal = pots * 15;
if (bottles < potsTotal + platesTotal) {
System.out.println("Not enough detergent, " + (potsTotal + platesTotal - bottles) + " ml. more necessary!");
break;
}
else
if(bottles >= potsTotal + platesTotal) {
System.out.println("Would you like to end the program? (Enter End)");
String enough = scan.next();
if (enough.equals("End")) {
if (bottles >= potsTotal + platesTotal) {
System.out.println("Detergent was enough!");
System.out.println(nrPlates + " dishes and " + nrPots + "pots were washed.");
System.out.printf("Leftover detergent %d ml.", bottles - potsTotal - platesTotal);
run = false;
System.out.println("Goodbye");
break;
}
}
}
}
cnt++;
}
}
}
I also changed your bottles slightly to use nextInt, though that depends on your use. If you're thinking the end user might type something like "The number of bottles are..." that'll be better, but otherwise why not use a simpler nextInt call?

if you want to use a scanner object for both strings and numbers you must parse the number:
Scanner scanner = new Scanner(System.in);
String str = scanner.nextLine();
int num = Integer.parseInt(scanner.nextLine());
or you can have two scanners(one for strings and another for numbers):
Scanner strScanner = new Scanner(System.in);
Scanner numScanner = new Scanner(System.in);
String str = strScanner.nextLine();
int num = numScanner.nextInt();

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;
}

User input on same line?

I'm new to Java so forgive me. I'm writing a small little Guessing Game program.
import java.util.Scanner;
public class GuessingGame {
static Scanner userInput = new Scanner(System.in);
public static void main(String[] args) {
int menuOption;
// Main Screen //
System.out.println("Guessing Game");
System.out.println("---------------------");
System.out.println("1.) Play Game");
System.out.println("2). Exit");
System.out.println();
while (true) {
System.out.print("Please select a menu option: ");
menuOption = userInput.nextInt();
if (menuOption == 2) {
System.out.println("Exiting the game. Thanks for playing!");
break;
} else if (menuOption == 1) {
System.out.println("Let's start the game!");
getRandomRange();
} else {
System.out.println("Sorry, that's not a valid option. Please try again.");
continue;
}
}
}
/**
* Determine the range of numbers to work with
*/
public static void getRandomRange() {
int min;
int max;
System.out.print("Choose a minimum number: ");
min = userInput.nextInt();
System.out.print("Choose a maximum value: ");
max = userInput.nextInt();
getRandomNumber(min, max);
}
public static void getRandomNumber(int min, int max) {
int randomNumber = (int) (Math.random() * (max - min + 1)) + min;
getAGuess(min, max, randomNumber);
}
public static void getAGuess(int min, int max, int randomNumber) {
int guess;
while (true) {
System.out.print("Guess a number between " + min + " and " + (max) + ": ");
guess = userInput.nextInt();
if (guess == randomNumber) {
System.out.println("Correct! The random number is: " + randomNumber);
break;
}
}
}
}
When I prompt the user to guess a number and the number is incorrect, I want to be able to flush immediately flush the input stream and enter another guess on the same line.
For example:
Guess a number between 0 and 5: I enter my guesses here on this one line only.
I could take the print out of the loop but in that case, if I enter an inccorect number, the cursor jumps to the next line.
Hope this makes sense. Thanks!

If your goal is only to clear the console, then you could do:
Runtime.getRuntime().exec("cls");
Or if you are on Linux or OS X:
Runtime.getRuntime().exec("clear");
Now if you add previous line that you wanted to keep, you will need to keep then in an Array and reprint after each clear.
This won't work in IDE's.
If you want a more system-independent way, there is a library named JLine (GitHub), which is designed for a better console usage. It actually contains a method clearScreen.
You could also do:
System.out.print("\033[H\033[2J");
This will clear the screen and return the cursor to the first row.

A quick and dirty solution...
public class Main {
public static final void main(String[] data) {
Scanner userInput = new Scanner(System.in);
int min = 0;
int max = 10;
int randomNumber = (int) ((Math.random() * max) + (min + 1));
while (true) {
System.out.print("Guess a number between " + min + " and " + max + ": ");
int guess = userInput.nextInt();
if (guess == randomNumber) {
System.out.println("Correct! The random number is: " + randomNumber);
break;
} else {
for (int i = 0 ; i < 25; i++) {
System.out.println();
}
}
}
}
}

Guessing Game, with a While loop

i'm currently trying to create a while loop for my program, a Guessing game. I've set it up so the user can create a max value i.e 1-500 and then the user can proceed to guess the number. When the number has been guessed, the User can press 1, to close, anything else to continue running the loop again.
My problem, is that the code gives me an error when trying to continue the loop, no compiling errros
This is my Code:
import java.util.Random;
import java.util.Scanner;
public class Gættespil2
{
public static void main(String[] args)
{
Random rand = new Random();
int TAL = rand.nextInt(20) + 1;
int FORSØG = 0;
Scanner input = new Scanner (System.in);
int guess;
int loft;
boolean win = false;
boolean keepPlaying = true;
while ( keepPlaying )
{
Scanner tastatur = new Scanner(System.in);
System.out.print("Indsæt loftets højeste værdi : ");
loft = tastatur.nextInt();
TAL = (int) (Math.random() * loft + 1);
while (win == false)
{
System.out.println(" Gæt et tal mellem 1 og "+ loft + "):: ");
guess = input.nextInt();
FORSØG++;
if (guess == TAL)
{
win = true;
}
else if (guess < TAL)
{
System.out.println("Koldere, gæt igen");
}
else if (guess > TAL) {
System.out.println("Varmere, Gæt igen!!");
}
}
System.out.println(" Tillykke du vandt...endeligt!!! ");
System.out.println(" tallet var" + TAL);
System.out.println(" du brugte " + FORSØG + " forsøg");
System.out.println("Slut spillet? tast 1.");
System.out.println("tryk på hvadsomhelst for at spille videre");
int userInt = input.nextInt();
if( userInt == 1)
{
keepPlaying = false;
}
}
}
}

Simple answer. You didn't initialize all the necessary values within your 'keepPlaying' loop before beginning a second round after the player successfully completed the first round. See annotations to your code, below:
import java.util.Random;
import java.util.Scanner;
public class GuessingGame
{
public static void main(String[] args)
{
Random rand = new Random();
int TAL = rand.nextInt(20) + 1;
int FORSØG = 0;
Scanner input = new Scanner (System.in);
int guess;
int loft;
boolean win = false;
boolean keepPlaying = true;
while ( keepPlaying )
{
Scanner tastatur = new Scanner(System.in);
System.out.print("Enter a maximum limit: ");
loft = tastatur.nextInt();
TAL = (int) (Math.random() * loft + 1);
// *** LOOK HERE ***
// Reset the 'win' flag here, otherwise the player receives an
// automatic win on all subsequent rounds following the first
win = false;
while (win == false)
{
System.out.println("Guess the number between one and "+ loft + "):: ");
guess = input.nextInt();
FORSØG++;
if (guess == TAL)
{
win = true;
}
else if (guess < TAL)
{
System.out.println("Colder, guess again!");
}
else if (guess > TAL) {
System.out.println("Warmer, guess again!");
}
}
System.out.println("You've found the number!");
System.out.println("The number was: " + TAL + ".");
System.out.println("You guessed " + FORSØG + " times.");
System.out.println("To quit, enter 1.");
System.out.println("Provide any other input to play again.");
int userInt = input.nextInt();
if( userInt == 1)
{
keepPlaying = false;
}
}
}
}
Sorry for the translation into English -- I had to make sure I was reading things correctly. You might also want to substitute "higher" and "lower" for "warmer" and "colder." "Warmer" and "colder" tend to suggest a proximity to the correct answer, as opposed to the direction in which that correct answer lies.

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 "?".