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How to make 'end game' method in java

so i made a game, in which user needs to guess the random number or letter. I want to make it so that when the user writes 'end game' during the game (when he guesses the number), he is being redirected to the menu (using the main(args); method). In fact, String value cannot be writen in int input. So when i write 'end game' during the game cycle, it just crashes. What should i do?
Heres code of my game:
import java.util.Scanner;
public class TwoGames {
public static void main(String[] args) { // main menu
Scanner scan = new Scanner(System.in);
System.out.println("Choose the game\n Type 'letter' or 'number' to choose the game");
String UserAnswer = "";
UserAnswer = scan.next();
if (UserAnswer.equalsIgnoreCase("number")) {
number(args);
}else if(UserAnswer.equalsIgnoreCase("letter")){
letter(args);
}
scan.close();
}
public static void letter (String[] args) {
Scanner scan = new Scanner(System.in);
String playAgain = "";
String ReTurn = "";
String Stop = "";
int numberOfTries = 0;
do {
System.out.println("Guess the Letter");
char randomLetter = (char) (Math.random() * 26 + 65);
char enteredLetter = 0;
while(true){
enteredLetter = Character.toUpperCase(scan.next().charAt(0));
numberOfTries = numberOfTries + 1;
if(enteredLetter==randomLetter)
{
System.out.println("Correct Guess");
System.out.println("The letter is:"+randomLetter);
System.out.println("It only took you " + numberOfTries + " tries! Good work!");
break;
}
else if(enteredLetter>randomLetter)
{
System.out.println("Incorrect Guess");
System.out.println("The letter entered is too high");
}
else if(enteredLetter<randomLetter)
{
System.out.println("Incorrect Guess");
System.out.println("The letter entered is too low");
}
}
System.out.println("Would you like to play again (y/n)?");
playAgain = scan.next();
} while (playAgain.equalsIgnoreCase("y"));
System.out.println("Thank you for playing! Goodbye! \n Type 'return' to return to main menu");
ReTurn = scan.next();
if (ReTurn.equalsIgnoreCase("return"))
main(args);
scan.close();
}
public static void number(String[] args) { //heres the number guessing game
Scanner scan = new Scanner(System.in);
String playAgain = "";
String ReTurn = "";
String Stop = "";//variable to stop game
do {
int theNumber = (int)(Math.random() * 100 + 1);
int numberOfTries = 0;
do {
int guess = 0;
while (guess != theNumber) {
System.out.println("Guess a number between 1 and 100:");
guess = scan.nextInt();
numberOfTries = numberOfTries + 1;
if (guess < theNumber)
System.out.println(guess + " is too low. Try again.");
else if (guess > theNumber)
System.out.println(guess + " is too high. Try again.");
else {
System.out.println(guess + " is correct. You win!");
System.out.println("It only took you " + numberOfTries + " tries! Good work!");
}
}
} while (Stop.equalsIgnoreCase("end game"));
main(args);// this sends user to main menu
System.out.println("Would you like to play again (y/n)?");
playAgain = scan.next();
} while (playAgain.equalsIgnoreCase("y"));
System.out.println("Thank you for playing! Goodbye! \n Type 'return' to return to main menu");
ReTurn = scan.next();
if (ReTurn.equalsIgnoreCase("return"))
main(args);
scan.close();
}
}
I am novice programmer, so yeah, thats might be a dumb question, because im learning. Anyway, any help and explanation would be useful.

To solve this problem, you should input a string, check if it equals to "End game" message and if not continue your code.
For example, replace this line:
guess = scan.nextInt();
In this code:
String input = scan.next();
if(input.equals("End game")){
main(args);
return;
}
guess = Integer.parseInt(input);
That code get a String input called input, check if he equals to "End game" and if not continue your guess loop.

Java 3.6 Checking inputs

Ask the user to "Input a number: " 4 times.
If the input is not a number, ask again.
Output "success." after they have entered 4 numbers.
Please answer this code for me using while, if, if else and do statements.
int counter; System.out.print("Input a number: ");
while(!(scan.hasNextInt()));{
for (int i = 0; i < 3; i++){
scan.next();
System.out.print("Input a number: ");
if (!(pass.equals(pass2))) {
counter++;
} else if (!(scan.hasNextInt())) {
}
}
if (counter >= 2) {
System.out.println("Input a number: ");
}
} else if (!(scan.hasNextInt())) { System.out.println("success."); }
This is very basic stuff but I am struggling.

int[] inputIntegers = new int[4]; // Array to save input
Scanner scan = new Scanner(System.in);
int counter = 0;
while(counter < 4) {
System.out.println("Input a number: ");
String input = scan.next();
if(input.matches("[-]?[0-9]*")){ // Checking, if input is an integer
inputIntegers[counter]=Integer.parseInt(input); // Persing string to integer
counter++;
} else {
System.out.println("Input is not an integer");
}
}
System.out.println("Success");
scan.close(); //Do not forget do close scanner

if a user inputs a letter instead of a number tell them it's not a number

I'm making a guessing game, all the code works fine except for that I want them to make a number to guess between, I can't seem to figure out how to make it so that if the user inputs a letter like "d" instead of a number like "15" it will tell them they can't do that.
Code:
import java.util.Scanner;
import java.util.Random;
public class GuessingGame {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
Random rand = new Random();
while (true) {
System.out.print("Pick a number: ");
int number = input.nextInt();
if (number != int) {
System.out.println("That's not a number");
} else if (number == int) {
int random = rand.nextInt(number);
break;
}
}
System.out.println("You have 5 attempts to guess the number or else you fail. Goodluck!");
System.out.println("");
System.out.println("Type 'begin' to Begin!");
System.out.print("");
String start = input.next();
if (start.equals("begin")) {
System.out.print('\f');
for(int i=1; i<6; i++) {
System.out.print("Enter a number between 1-" + number + ": ");
int number = input.nextInt();
if (number > random) {
System.out.println("Too Big");
System.out.println("");
} else if (number < random) {
System.out.println("Too Small");
System.out.println("");
} else if (number == random) {
System.out.print('\f');
System.out.println("Correct!");
break;
}
if (i == 5) {
System.out.print('\f');
System.out.println("You have failed");
System.out.println("Number Was: " + random);
}
}
} else if (start != "begin") {
System.out.print('\f');
System.out.println("Incorrect Command");
System.out.println("Please Exit Console And Retry");
}
}
}

use try catch
for example
try{
int a=sc.nextInt();
}catch(Exception e){
System.out.println("not an integer");
}

You could use nextLine() instead of nextInt() and check the out coming String if it matches() the regular expression [1-9][0-9]* and then parse the line with Integer.valueOf(str).
Like:
String str=input.nextLine();
int i=0;
if(str.matches("[1-9][0-9]*"){
i=Integer.valueOf(str);
} else {
System.out.println("This is not allowed!");
}
I hope it helps.

Do something like this:
Scanner scan = new Scanner(System.in);
while(!scan.hasNextInt()) { //repeat until a number is entered.
scan.next();
System.out.println("Enter number"); //Tell it's not a number.
}
int input = scan.nextInt(); //Get your number here

How to check if user input is String, double or long in Java

I'm a beginner in java. I want to check first if the user input is String or Double or int. If it's String, double or a minus number, the user should be prompted to enter a valid int number　again. Only when the user entered a valid number should then the program jump to try. I've been thinking for hours and I come up with nothing useful.Please help, thank you!
import java.util.InputMismatchException;
import java.util.Scanner;
public class Fizz {
public static void main(String[] args) {
System.out.println("Please enter a number");
Scanner scan = new Scanner(System.in);
try {
Integer i = scan.nextInt();
if (i % 3 == 0 && (i % 5 == 0)) {
System.out.println("FizzBuzz");
} else if (i % 3 == 0) {
System.out.println("Fizz");
} else if (i % 5 == 0) {
System.out.println("Buzz");
} else {
System.out.println(i + "は3と5の倍数ではありません。");
}
} catch (InputMismatchException e) {
System.out.println("");
} finally {
scan.close();
}
}

One simple fix is to read the entire line / user input as a String.
Something like this should work. (Untested code) :
String s=null;
boolean validInput=false;
do{
s= scannerInstance.nextLine();
if(s.matches("\\d+")){// checks if input only contains digits
validInput=true;
}
else{
// invalid input
}
}while(!validInput);

You can also use Integer.parseInt and then check that integer for non negativity. You can catch NumberFormatException if the input is string or a double.
Scanner scan = new Scanner(System.in);
try {
String s = scan.nextLine();
int x = Integer.parseInt(s);
}
catch(NumberFormatException ex)
{
}

Try this one. I used some conditions to indicate the input.
Scanner scan = new Scanner(System.in);
String input = scan.nextLine();
int charCount = input.length();
boolean flag = false;
for(int x=0; x<charCount; x++){
for(int y=0; y<10; y++){
if(input.charAt(x)==Integer.toString(y))
flag = true;
else{
flag = false;
break;
}
}
}
if(flag){
if(scan.hasNextDouble())
System.out.println("Input is Double");
else
System.out.println("Input is Integer");
}
else
System.out.println("Invalid Input. Please Input a number");

Try this. It will prompt for input until an int greater than 0 is entered:
System.out.println("Please enter a number");
try (Scanner scan = new Scanner(System.in)) {
while (scan.hasNext()) {
int number;
if (scan.hasNextInt()) {
number = scan.nextInt();
} else {
System.out.println("Please enter a valid number");
scan.next();
continue;
}
if (number < 0) {
System.out.println("Please enter a number > 0");
continue;
}
//At this stage, the number is an int >= 0
System.out.println("User entered: " + number);
break;
}
}

boolean valid = false;
double n = 0;
String userInput = "";
Scanner input = new Scanner(System.in);
while(!valid){
System.out.println("Enter the number: ");
userInput = input.nextLine();
try{
n = Double.parseDouble(userInput);
valid = true;
}
catch (NumberFormatException ex){
System.out.println("Enter the valid number.");
}
}

How to add for loops to if statements?

In my code below I am not sure what order to put it in to work properly.
I first want it to print out for the user to select an option which it does, then if they select 1 it asks them their name and verifies it with the loop etc.
When I enter a name it starts to just loop the question enter your name and I don't know how to fix it.
Do I need to add more statements to my program, if I do then can I still use if statements for the user to select an option?
import java.util.Scanner;
public class username {
public static void main(String[] args) {
{
int UseLift;
int AuditReport;
int ExitLift;
int a;
UseLift = 1;
AuditReport = 2;
ExitLift = 3;
}
System.out.println("choose an option");
System.out.println("Uselift(1)");
System.out.println("see audit report(2)");
System.out.println("Exit Lift(3)");
Scanner d = new Scanner(System.in);
int a = d.nextInt();
Scanner kb = new Scanner(System.in);
// array containing usernames
String[] name = {"barry", "matty", "olly", "joey"}; // elements in array
if (a == 1) {
System.out.println(" Enter your name ");
}
String name1 = kb.nextLine();
boolean b = true;
int j = 0;// counter will start at 0
outerloop:
while (j < 3) {
System.out.println("Enter your name");
}
for (int i = 0; i < name.length; i++) {
if (name[i].equals(name1)) {
System.out.println("you are verified you may use the lift, calling lift ");
}
break;// to stop loop checking names
}
System.out.println("Username Invalid");
j++;
if (a == 2) {
System.out.println("");
}
if (a == 3) {
System.out.println(" Please Exit Lift ");
}
}
}

here you go:
public static void main(String... args) {
String[] verifiedNames = { "barry", "matty", "olly", "joey" };
System.out.println("choose an option");
System.out.println("Uselift(1)");
System.out.println("see audit report(2)");
System.out.println("Exit Lift(3)");
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
switch (choice) {
case 1:
scanner.nextLine(); // get '\n' symbol from previous input
int nameAttemptsLeft = 3;
while (nameAttemptsLeft-- > 0) {
System.out.println(" Enter your name ");
String name = scanner.nextLine();
if (Arrays.asList(verifiedNames).contains(name)) {
System.out.println("dear " + name + " you are verified " +
"you may use the lift, calling lift ");
break; // break out of loop
}
}
if (nameAttemptsLeft < 0) {
System.out.println("Username Invalid");
}
break;
case 2:
System.out.println("option 2");
break;
case 3:
System.out.println(" Please Exit Lift ");
break;
}
scanner.close();
}

Your while loop below:
while (j < 3) {
System.out.println("Enter your name");
}
will loop forever since j is not incrementing (j++). I believe you've mis-matched your curly braces at some point.