My code is running fine, but every line where I use a scanner it warns me that there is a "Resource leak; 'userGuess' is never closed" I don't understand what it means and could use some help solving it. Also if there is anything else in my code worth fixing I could use the help. Be warned I have a limited knowledge of Java programming. I also cannot get my TryCounter++ to work...
package masterMind2_1;
import java.util.Scanner;
public class MasterMind2_1 {
public static void main(String[] args) {
System.out.println("This is MasterMind, a logic game");
System.out.println("To win you must guess correctly where each number is(The Numbers Range from 1-4)");
System.out.println("You will be told if you get one correct");
System.out.println("You will only get 10 tries, then you lose");
System.out.println("Lets begin");
//Declare Array
int [] answerArray;
answerArray= new int [4];
//Initialize Array
//Change these value to change the answers needed to win
answerArray[0]=2;
answerArray[1]=3;
answerArray[2]=2;
answerArray[3]=2;
// //Create Board
// System.out.println("-- -- -- --");
boolean guessedAll = false;
int guessedCount=0;
int tryCounter=0;
while(tryCounter<9 || !guessedAll){
System.out.println("What is the first Number?");
Scanner userGuess = new Scanner(System.in);
int num = userGuess.nextInt();
if (num==answerArray[0]) {
guessedCount++;
}
System.out.println("What is the Second Number?");
Scanner userGuess1 = new Scanner(System.in);
int num1 = userGuess1.nextInt();
if (num1==answerArray[1]) {
guessedCount++;
}
System.out.println("What is the Third Number?");
Scanner userGuess2 = new Scanner(System.in);
int num2 = userGuess2.nextInt();
if (num2==answerArray[2]) {
guessedCount++;
}
System.out.println("What is the Fourth Number?");
Scanner userGuess3 = new Scanner(System.in);
int num3 = userGuess3.nextInt();
if (num3==answerArray[3]) {
guessedCount++;
}
System.out.println("Your guess was "+ num+" "+num1+" "+num2+" "+num3);
if (num==answerArray[0]) {
System.out.println("First number was correct");
} else {
System.out.println("First number was incorrect");
}
if (num1==answerArray[1]) {
System.out.println("Second number was correct");
} else {
System.out.println("Second number was incorrect");
}
if (num2==answerArray[2]) {
System.out.println("Third number was correct");
} else {
System.out.println("Third number was incorrect");
}
if (num3==answerArray[3]) {
System.out.println("Fourth number was correct");
} else {
System.out.println("Fourth number was incorrect");
}
if (guessedCount==4) {
System.out.println("YAY you won!!");
guessedAll=true;
tryCounter=10;
} else {
System.out.println("Try again, except this time don't fail!");
guessedAll=false;
tryCounter++;
guessedCount=0;
}
}//What if I collected all of the values first
} //then told them if they were right or Wrong?
//Black and White Pegs?
//Fix TryCounter...Why isn't it working
}
Thank you for the Help!
The error message is telling you that you never call the close() method on your Scanner object. A worse problem is that you create multiple Scanners when you only need one.
As for tryCounter not working...
while(tryCounter<9 || !guessedAll)
This will keep looping if either part of the condition is true. My guess is that !guessedAll is evaluating to true beyond 9 guesses, so your loop keeps running. You'll need to change the || to an && to get it stop looping after 9 tries. (Also, print out the values of your variables or use a debugger so you can verify that they are changing when you expect them to.)
Related
This is my first time here. I'm starting to learn how to code, so I honestly hope this question I have is not something I can find over here! (I promise I searched for a while, but since I'm a noob in this topic, I didn't found anything understandable for me in order to resolve my doubt).
I'm doing a simple game in JAVA, in which the program generates a random number and the player has to guess the number generated.
When the player enters a number, the game displays a hint, saying if it is higher or lower than the number generated randomly.
The program itself works fine if you enter just numbers, but I want to add a try-catch statement to handle bad user input.
I tried using the statement as I show in my code, but I can't understand why it's not working properly, because when I enter something different of a number, the exception is catched and it prints on console the System.out.println(), but program terminates when this happens.
I would like to try-catch just to get the exception of entering not a number without terminating the program every time the exception is catched.
How can I fix this?
Thanks a lot for your help!
import java.util.Scanner;
public class HiLo {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in); //Creates Scanner object to read from keyboard
String playAgain = ""; //if == y, game restarts
try {
do {
// Create a random number for the user to guess
int theNumber = (int)(Math.random() * 100 + 1);
//System.out.println(theNumber); //Uncoment this in case we want to know the number (for testing).
int guess = 0; //Number entered by the player
int count = 0; //Number of tries of guessing the number
while(guess != theNumber){
System.out.println("Guess a number between 1 and 100:");
guess = scan.nextInt(); //Reads the number typed on the keyboard by the player
count++; //Plus 1 every time a number is entered
System.out.println("You entered " + guess +".");
if(guess < theNumber) { //If number entered is smaller
System.out.println("The number is bigger" + ", try again!");
System.out.println("Number of tries: " + count);
} else if(guess > theNumber) { //If number entered is bigger
System.out.println("The number is smaller" + ", try again!");
System.out.println("Number of tries: " + count);
} else { //If both previous cases are false
System.out.println("Congratulations! You've found the number!");
}
}
//Once guess == theNumber
System.out.println("Number of tries: " + count);
System.out.println("Play again? (y/n)");
playAgain = scan.next(); //Reads the String entered from keyboard by the player
}
while(playAgain.equalsIgnoreCase("y")); //If player enters y, start again.
//Otherwise
System.out.println("Thank you for playing! Goodbye :)");
} catch (Exception e) {
System.out.println("Incorrect entering! Please enter a number between 1 and 100.");
}
scan.close(); //Close scanner
} //Close main
} //Close class
place try-catch inside the while loop and reinstantiate the scanner object (scan = new Scanner(System.in) inside the catch block.
while (guess != theNumber) {
try {
System.out.println("Guess a number between 1 and 100:");
guess = scan.nextInt(); // Reads the number typed on the
// keyboard by the player
count++; // Plus 1 every time a number is entered
System.out.println("You entered " + guess + ".");
if (guess < theNumber) { // If number entered is smaller
System.out.println("The number is bigger" + ", try again!");
System.out.println("Number of tries: " + count);
} else if (guess > theNumber) { // If number entered is
// bigger
System.out.println("The number is smaller" + ", try again!");
System.out.println("Number of tries: " + count);
} else { // If both previous cases are false
System.out.println("Congratulations! You've found the number!");
}
} catch (Exception e) {
System.out.println("Incorrect entering! Please enter a number between 1 and 100.");
scan = new Scanner(System.in);
}
}
You need to understand the working of the try-catch block. You don't need to surround the entire code within try. Just put that part of the code which causes an exception. So, in your case just surround guess = scan.nextInt(); with try and then catch an exception. Because, here this statement raises an exception when the input is not an integer. This way you can ensure that the user input is valid for each iteration of the while(guess != theNumber) loop.
Edit_1:
I removed the try-catch blocks from your code and added the following & it works fine for me:
try{
guess = scan.nextInt();} //Reads the number typed on the keyboard by the player
catch (InputMismatchException e){
System.out.println("Incorrect entering! Please enter a number between 1 and 100.");
scan.nextLine();
continue;
}
I want to create a program that gives you three tries to find any given number. It's going to essentially be a guessing game. The problem is, I have to do this without any loops. So far, I'm only able to get input from the user, read that input and tell them if they've won or 'lost' the game. The program only runs once and stops(as expected).
I was told that it could be done without loops, albeit with a lot more code. Can you guys let me know what I'm doing wrong here and give me some pointers on what I should change? If you need clarification let me know.
Thanks.
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner ran = new Scanner(System.in);
System.out.println("Enter a number: ");
int x = ran.nextInt();
if (x < 3) {
System.out.println("Too low. Try again.");
System.out.println("Enter a number: ");
} else if (x > 3) {
System.out.println("Too high. Try again");
} else if(x == 3) {
System.out.println("You win. Nice job.");
} else {
System.out.println("You lose");
}
System.out.println("Number Guessing Game (c) 2017 Anna Gibson");
}
}
You can do this using recursion. See this program. Find explanations within comments.
import java.util.Scanner;
public class HelloWorld {
private static Scanner ran = new Scanner(System.in);
//this is number of tries you want to give to user
private static int counter = 5;
//The actual number
private static final int NUM = 3;
public static boolean guessingMachine() {
//counter indicates that number of attempts remaining
if(counter == 0) {
return false;
}
counter--;
System.out.println("Enter a number: ");
int x = ran.nextInt();
if (x < NUM) {
System.out.println("Too low. Try again.");
//try again... call this method again
return guessingMachine();
} else if (x > NUM) {
System.out.println("Too high. Try again");
//try again... call this method again
return guessingMachine();
} else {
//x == NUM success
return true;
}
}
public static void main(String[] args) {
boolean result = guessingMachine();
if(result)
System.out.println("You win. Nice job.");
else
System.out.println("You lose");
System.out.println("Number Guessing Game (c) 2017 Anna Gibson");
}
}
You could next conditions:
get user input
if input is correct, congratulation user and exit
else
get user input //second attempt
if input is correct, congratulation user and exit
...
You can continue from there. The code you provided, where you tell the user if they are too high or low, would have to be included in each of the branches of the pseudocode above.
I think the main purpose of this exercise is intended for you to strengthen your nested if-else concepts.
import java.util.Scanner;
public class HelloWorld{
public static void main(String []args){
int num=3;
int count=1;
Scanner ran = new Scanner(System.in);
System.out.println("Enter a number: ");
int x = ran.nextInt();
if(x>num || x<num)
{
System.out.println("incorrect guess");
count++;
System.out.println("Enter a number: ");
x = ran.nextInt();
if(x>num || x<num)
{
System.out.println("incorrect guess");
count++;
System.out.println("Enter a number: ");
x = ran.nextInt();
if(x>num || x<num)
{
System.out.println("incorrect guess YOU LOSE");
}
else
{
System.out.println("YOU WIN");
}
}
else
{
System.out.println("YOU WIN");
}
}
if(x==num && count==1)
{
System.out.println("YOU WIN");
}
System.out.println("Number Guessing Game (c) 2017 Anna Gibson");
}
}
im trying to do two checks with a while loop:
1) To show "error" if the user inputs something other than an int
2) Once the user entered an int, if it is one digit, show "two digits only" and keep the loop on until a two digit int has been entered (so an IF should be used as well)
Currently I only have the first part done:
Scanner scan = new Scanner(System.in);
System.out.println("Enter a number");
while (!scan.hasNextInt()) {
System.out.println("error");
scan.next();
}
However, if possible, I would like to have both checks in one while loop.
And that's where I'm stuck...
Since you already have two answers. This seems a cleaner way to do it.
Scanner scan = new Scanner(System.in);
String number = null;
do {
//this if statement will only run after the first run.
//no real need for this if statement though.
if (number != null) {
System.out.println("Must be 2 digits");
}
System.out.print("Enter a 2 digit number: ");
number = scan.nextLine();
//to allow for "00", "01".
} while (!number.matches("[0-9]{2}"));
System.out.println("You entered " + number);
As said above you should always take the input in as string and then try
and parse it for an int
package stackManca;
import java.util.Scanner;
public class KarmaKing {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String input = null;
int inputNumber = 0;
while (scan.hasNextLine()) {
input = scan.next();
try {
inputNumber = Integer.parseInt(input);
} catch (Exception e) {
System.out.println("Please enter a number");
continue;
}
if (input.length() != 2) {
System.out.println("Please Enter a 2 digit number");
} else {
System.out.println("You entered: " + input);
}
}
}
}
First take the input as a String. If it is convertible to Int then you do your checks, else say 2 digit numbers are acceptable. If it is not convertible to a number throw an error. All this can be done in one while loop. And you would like to have a "Do you want to continue? " kind of a prompt and check if the answer is "yes" / "No." Break from the while loop accordingly.
To have it as one loop, it's a bit messier than two loops
int i = 0;
while(true)
{
if(!scan.hasNextInt())
{
System.out.println("error");
scan.next();
continue;
}
i = scan.nextInt();
if(i < 10 || >= 100)
{
System.out.println("two digits only");
continue;
}
break;
}
//do stuff with your two digit number, i
vs with two loops
int i = 0;
boolean firstRun = true;
while(i < 10 || i >= 100)
{
if(firstRun)
firstRun = false;
else
System.out.println("two digits only");
while(!scan.hasNextInt())
{
System.out.println("error");
scan.next();
}
i = scan.nextInt();
}
//do stuff with your two digit number, i
Ive no idea if my title made sense but here is the code ©
import java.util.InputMismatchException;
import java.util.Scanner;
public class Gussing {
public static void theGame(Scanner input){
int randomNum= (int)(Math.random()*101);//randomizes a number between 0-100 inclusive of both
System.out.println(randomNum); //for debugging purposes
int attemptCounter = 0; //counts how many attempts the user make
System.out.print("Welcome to the guess-the number game! Enter your guess: ");
while(true){
System.out.println("here is bad input");
try{
System.out.println("here is after the bad input");
int userInput= input.nextInt();
if (userInput==randomNum) //when usr input and generated random number are equal we print how many attempts
{
attemptCounter++;
System.out.println("Congrats you made the right guess after "+ attemptCounter + " attempts!");
break;
}
if(userInput<randomNum){
attemptCounter++;
System.out.print("Too low! Try again: ");
}
else {
attemptCounter++; //else clause does the opposite of if clause
System.out.print("Too high! Try again: ");
}
}
catch( Exception e){
System.out.println("Invalid input");
}
}
}
public static void main(String[] args){
Scanner input = new Scanner (System.in);
theGame (input);
System.out.println("Play again? (Y/N)");
try{
char answer=input.next().toLowerCase().charAt(0);
//toLowerCase method so that N =n = no !
if (answer =='y') theGame (input);
else if (answer =='n') System.out.println("Good bye");
input.close(); //no more input data
}
catch(Exception e){
System.out.println("invalid input");
}
}
}
so when the user types in the wrong type i.e not int it prints out invalid input. This is however not the problem the problem is that it prints that out infinitely. I tried adjusting the try catchblocks but it didnt help at all
nextInt doesnt remove non-integer data from the input buffer so it gets recycled indefinitely unless the data is consumed. In this case an InputMismatchException is thrown by the method so you could write your exception block as
} catch (InputMismatchException e) {
System.out.println("Invalid input " + input.nextLine());
}
I'm currently creating my first game which is executed in a console.
I've been asked to validate an input which can be done with a simple code. The goal is to input, and then validate if that number is an integer, and is on a range of 1-4. If possible, the problem should be solved with basic algorithm.
The problem is that it won't give me the result I wanted. It works when I enter a string, but it loops on every number I put including the number in the range. Does anyone know why?
public class Menu {
public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
int input = 0;
int min = 1;
int max = 4;
boolean inputValidate;
System.out.println("Main Menu");
System.out.println("=========");
System.out.println("1. Play Game");
System.out.println("2. About");
System.out.println("3. View Saved Games");
System.out.println("4. Exit");
System.out.println("");
do {
System.out.print(">> ");
if (!scanner.hasNextInt()) {
inputValidate = false;
System.out.println("Not a number. Please input number 1-4.");
scanner.nextLine();
} else if (input <= max && !(input < min)) // if input <= 4 and input is not less than 1
{
input = scanner.nextInt();
inputValidate = true;
} else {
inputValidate = false;
System.out.println("Not in range. Please input number 1-4.");
scanner.nextLine();
}
} while (!(inputValidate));
switch (input) {
case 1:
break;
case 2:
System.out.println("Good work!");
break;
case 3:
break;
case 4:
break;
}
}
}
}
Because you instantiate input to be 0, but never give the user an opportunity to change this, the conditions for the first two conditionals are always false (nothing is read from the Scanner and 0 is not between min and max). Therefore, the program falls through to the else every time. Just add a statement before the do-while that will obtain a value for input from the user.
input = scanner.nextInt();
// your do-while loop
(You'll also probably have to adjust the code slightly to get the type of interaction you're looking for. Hint - you're reading two values from the user.)
As Clint said the problem was in your input. Here's a demo how you can fix this,
try (Scanner scanner = new Scanner(System.in)) {
int input = 0;
int min = 1;
int max = 4;
boolean inputValidate = false;
System.out.println("Main Menu");
System.out.println("=========");
System.out.println("1. Play Game");
System.out.println("2. About");
System.out.println("3. View Saved Games");
System.out.println("4. Exit");
System.out.println("");
do {
System.out.print(">> ");
try {
input = scanner.nextInt();
if (input >= min && input <= max) {
inputValidate = true;
} else {
System.out
.println("Not in range. Please input number 1-4.");
scanner.nextLine();
}
} catch (InputMismatchException exception) {
System.out
.println("Not a number. Please input number 1-4.");
scanner.nextLine();
}
} while (!(inputValidate));