I am doing a guessing game where in I can input 1-100 but I am having a trouble in only accepting numbers if I typed a letter when I first run the program it will give me error and execute the program instantly image herebut if ityped number after I start the program and type letter next it give me a wrong message it should only display message saying "invalid input".image here Any suggestion thanks.
package m1;
import java.util.InputMismatchException;
import java.util.Scanner;
public class M1{
public static void main(String[] args) {
Scanner Scanner = new Scanner(System.in);
int between = 100;
int secretNumber = (int)(Math.random()*between);
int inputNum = 0;
int guesses = 0;
System.out.println("Please enter your guess: ");
inputNum = Scanner.nextInt();
guesses++;
while (inputNum != secretNumber) {
try {
// number too high or too low
if (inputNum > 100 || inputNum < 1) {
System.out.println("Out of Range!");
System.out.println("Enter a guess between 1 and " + between + ".");
inputNum = Scanner.nextInt();
}
// less than secretNumber
if (inputNum < secretNumber) {
System.out.println("Too Low...Try Again!");
inputNum = Scanner.nextInt();
guesses++;
}
// greater than secretNumber
if (inputNum > secretNumber) {
System.out.println("Too High...Try Again!");
inputNum = Scanner.nextInt();
guesses++;
}
}
catch(InputMismatchException e){
System.out.println("Invalid Input");
Scanner.next();
}
}
System.out.println("\nWell done! The secret number was " + secretNumber + "." + "\nYou took " + guesses + " guesses.");
}
}
Generally, name variable names in java using camelCase in most cases.
You don't actually need to catch any exception in your case as you can simply do scanner.next() if scanner.hasNextInt() is false. Prompting the user to enter specifically a number this time.
Try the below code:
import java.util.Scanner;
import java.util.concurrent.ThreadLocalRandom;
class Main {
private static final String GUESS_PROMPT_PATTERN = "Please enter a guess between %d and %d inclusive: ";
private static final String WIN_PROMPT_PATTERN = "Well done! The secret number was %d. You took %d guesses.\n";
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int minimumGuess = 1, maximumGuess = 100;
int secretNumber = ThreadLocalRandom.current().nextInt(minimumGuess, maximumGuess + 1);
int guesses = 0;
String guessPrompt = String.format(GUESS_PROMPT_PATTERN, minimumGuess, maximumGuess);
System.out.println("Lec's Guessing Game");
System.out.println("====================");
System.out.print(guessPrompt);
while (scanner.hasNext()) {
if (scanner.hasNextInt()) {
guesses++;
int inputNum = scanner.nextInt();
if (inputNum == secretNumber) {
break;
}
// Input number too high or too low.
if (inputNum > maximumGuess || inputNum < minimumGuess) {
System.out.println("Out of Range!");
scanner.nextLine();
System.out.print(guessPrompt);
}
// Input number was less than the secret number.
else if (inputNum < secretNumber) {
System.out.println("Too Low... Try Again!");
System.out.print(guessPrompt);
}
// Input number was greater than the secret number.
else {
System.out.println("Too High... Try Again!");
System.out.print(guessPrompt);
}
} else {
System.out.print("ERROR: Invalid Input");
System.out.print("Please enter a number: ");
scanner.next();
}
}
System.out.printf(WIN_PROMPT_PATTERN, secretNumber, guesses);
}
}
Related
I'm working on a homework problem of creating a guessing game. I've got that part working, but we have to validate the input. I've tried using hasNextInt, but I keep getting an error saying "int cannot be dereferenced" and points to the "!guess.hasNextInt" code.
I've tried many iterations, but I still get the same error. The code I'm including is just my most recent try.
How do I get hasNextInt to work or how else should I validate the input?
import java.util.Scanner;
public class GuessNumber {
public static void main(String[] args) {
int num = (int) (Math.random() * 101);
Scanner input = new Scanner(System.in);
System.out.println("Welcome to my Guessing Game!");
int guess = -1;
//Loop goes as long as guess doesn't equal num
while (guess != num) {
System.out.print("Guess a number between 1 and 100: ");
guess = input.nextInt();
//Validates input
while (!guess.hasNextInt()) {
System.out.println("Invalid response, try again.");
in.next();
}
if (guess == num)
System.out.println("Correct!");
else if (guess < num)
System.out.println("Your guess was too low");
else
System.out.println("Your guess was too high");
}
}
}
i fixed the code:
public static void main(String[] args) {
int num = (int) (Math.random() * 101);
System.out.println(num);
Scanner input = new Scanner(System.in);
System.out.println("Welcome to my Guessing Game!");
int guess = -1;
//Loop goes as long as guess doesn't equal num
while (guess != num) {
System.out.print("Guess a number between 1 and 100: ");
guess = input.nextInt();
if (guess == num) {
System.out.println("Correct!");
break;}
else if (guess < num)
System.out.println("Your guess was too low");
else
System.out.println("Your guess was too high");
//Validates input
while (!input.hasNextInt()) {
System.out.println("Invalid response, try again.");
input.next();
}
}
}
if the user guessed the number the game ends using break
in while (!guess.hasNextInt()) you were using a integer where it's expect the Scanner input
If you want to parse your number you can use Integer.parseInt() method as shown. Also you are using hasNextInt() incorrectly. You are also not storing in.next() value in any variable.
import java.util.Scanner;
public class GuessNumber {
public static void main(String[] args) {
int num = (int)(Math.random() * 101);
Scanner input = new Scanner(System.in);
System.out.println("Welcome to my Guessing Game!");
int guess = -1;
//Loop goes as long as guess doesn't equal num
while (true) {
System.out.print("Guess a number between 1 and 100: ");
String numberString = input.nextLine();
//Validates input
try {
guess = Integer.parseInt(numberString);
if (guess == num) {
System.out.println("Correct!");
break;
} else if (guess < num)
System.out.println("Your guess was too low");
else
System.out.println("Your guess was too high");
} catch (Exception e) {
System.out.println("Invalid response, try again.");
}
}
}
}
I need help coding a set of statements of data validation that checks if a user entry is within a range of 0 and 100, and anything the user types that ISNT a non-decimal integer between 1 and 100 should display an error message. Also I need a way to code how I can get a "goodbye" output to only display if the user enters "n" not "n" and "y." N meaning no and y meaning yes.
Heres my code.
import java.util.Scanner;
public class GuessingGameCalc {
private static void displayWelcomeMessage(int max) {
System.out.println("Welome to the Java Guessing Game!");
System.out.println(" ");
System.out.println("I'm thinking of a number between 1 and" + " " + max + " " + "let's see if you guess what it is!");
System.out.println(" ");
}
public static int calculateRandomValue(int max) {
double value = (int) (Math.random() * max + 1);
int number = (int) value;
number++;
return number;
}
public static void validateTheData(int count) {
if( count < 3) {
System.out.println("Good job!");
} else if (count < 7) {
System.out.println("Need more practice.");
} else{
System.out.println("Need way more practice.");
}
}
public static void main(String[] args) {
final int max = 100;
String prompt = "y";
displayWelcomeMessage(max);
int unit = calculateRandomValue(max);
Scanner sc = new Scanner(System.in);
int counter = 1;
while (prompt.equalsIgnoreCase("y")) {
while (true) {
System.out.println("Please enter a number.");
int userEntry = sc.nextInt();
if (userEntry < 1 || userEntry > max) {
System.out.println("Invalid guess! Guess again!");
continue;
}
if (userEntry < unit) {
if ( (unit - userEntry) > 10 ) {
System.out.println("Way Too low! Guess higher!");
} else {
System.out.println("Too low! Guess higher!");
}
} else if (userEntry > unit) {
if( (userEntry - unit) > 10 ){
System.out.println("Way Too high! Guess lower!");
} else {
System.out.println("Too high! Guess lower!");
}
} else {
System.out.println("Congratulations! You guessed it in" + " " + counter + " " + "tries!\n");
validateTheData(counter);
break;
}
counter++;
}
System.out.println("Would you like to try again? Yes or No?");
prompt = sc.next();
System.out.println("Goodbye!");
}
}
}
Instead of using .nextInt() rather use .nextLine(), which returns a String and then parse it to an int and catch the NumberFormatException
So basically you'll have this structure:
try {
int userEntry = Integer.parseInt(sc.nextLine());
...
} catch (NumberFormatException nfe) {
System.out.println("Please enter a valid number.");
}
Oh, just a comment on the rest of your code. You don't really need two while loops, one will be more than sufficient.
I am writing a program that will ask the user to guess a random number 6 times. The program has to ask if they want to play again and will keep a running total of the wins/losses.
How would I have the program rerun?
heres the code:
import java.util.Scanner;
import java.util.Random;
public class Project {
public static void main(String[] args) {
String input;
double guess = 0;
int number;
double wins = 0;
double losses = 0;
String repeat;
Scanner keyboard = new Scanner(System.in);
Random randomNumbers = new Random();
System.out.println("Welcome to Higher/Lower!");
System.out.println("Enter your name: ");
input = keyboard.nextLine();
while(input.equalsIgnoreCase("yes")); {
number = randomNumbers.nextInt(100) + 1;
System.out.println("I've chosen my number, " + input + "You only have 6 tries, good luck!"); }
for(int num = 1; number != guess && number <= 6; num++) {
System.out.println("Enter guess " + num + ":");
guess = keyboard.nextDouble();
if(guess < number)
System.out.println("higher.");
else if(guess > number)
System.out.println("lower.");
else
System.out.println("Congratulations!"); }
if(guess == number) {
System.out.println("You guesses my number!"); wins++; }
if(guess != number) {
System.out.println("Sorry, " + input + " my number was " + number +
"You lose!"); losses++; }
System.out.println("Do you want to play again? (Yes/No): ");
repeat = keyboard.nextLine();
if(input.equalsIgnoreCase("no")); {
System.out.println("Thanks for playing!"); }
System.out.println(wins + " wins");
System.out.println(losses + " losses");
}
}
It is skipping over asking me if i want to play again or not and i dont know what kind of loop to use
Wihtout your code, I'm assuming this is what you need.
boolean doContinue = true;
do {
//guess random number 6 times
//do you want to continue?
// yes -> doContinue = true;
// no -> doContinue = false;
} while (doContinue );
I would suggest making your loop a do-while loop like this:
do {
for (int i=0; i<6; i++){
/*
insert code for the guessing/checking/etc.
*/
}
System.out.print("Would you like to continue? [Y/n] ");
} while (scan.next().toUpperCase().charAt(0) != 'Y');
How would I limit the tries of a simple game to just three? I would think you would use a boolean. But not sure.
import java.util.Scanner;
public class guess {
public static void main(String[] args) {
int randomN = (int) (Math.random() * 10) + 1;
Scanner input = new Scanner(System.in);
int guess;
System.out.println("Enter a number between 1 and 10.");
System.out.println();
do {
System.out.print("Enter your guess: ");
guess = input.nextInt();
if (guess == randomN) {
System.out.println("You won!");
} else if (guess > randomN) {
System.out.println("Too high");
} else if (guess < randomN) {
System.out.println("Too low");
}
} while (guess != randomN);
}
}
int attempts = 0;
do{
attempts++;
....
}while(guess != randomN && attempts < 3);
Use a flag. Initialize it as 0. If guess is correct then reset it as 0. If not increase by 1. Before each guess, check if flag > 2. If no let continue, if yes break.
You can increment during the failure of a guess. I believe the variable should be located outside of the loop. Then what's left is to add a portion that notifies the user of a failure when guesses run out.
public static void main(String[]args) {
int rNumber = (int)(Math.random() * 10) + 1;
Scanner input = new Scanner(System.in);
int guess;
int tries = 0;
int success = 0;
System.out.println("Enter a number between 1 and 10.");
System.out.println();
do {
System.out.println("Enter your guess: ");
guess = input.nextInt();
if(guess == rNumber) {
System.out.println("You guessed right! You win!");
success++;
} else if (guess < rNumber) {
System.out.println("Too low");
tries++;
} else if (guess > rNumber) {
System.out.println("Too high.");
tries++;
}
} while(tries != 3 && success != 1 || success != 1);
}
How would I make my game have multiple lives until I can finally get the correct number?
import java.util.Scanner;
public class GuessNumberOneTime {
public static void main(String[] args) {
// Generate a random number to be guessed
int number = (int)(Math.random() * 101);
Scanner input = new Scanner(System.in);
System.out.println("Guess a magic number between 0 and 100");
// Prompt the user to guess the number
System.out.print("\nEnter your guess: ");
int guess = input.nextInt();
if (guess == number)
System.out.println("Yes, the number is " + number);
else if (guess > number)
System.out.println("Your guess is too high");
else
System.out.println("Your guess is too low");
}
In order for your program to have multiple lives initialize a variable called guess and then run the int number through a while loop until the correct number has been chosen! Here’s an example of what you could do:
import java.util.Scanner;
public class GuessNumber {
public static void main(String[] args) {
// Generate a random number to be guessed
int number = (int)(Math.random() * 101);
Scanner input = new Scanner(System.in);
System.out.println("Guess a magic number between 0 and 100");
int guess = -1;
while (guess != number) {
// Prompt the user to guess the number
System.out.print("\nEnter your guess: ");
guess = input.nextInt();
if (guess == number)
System.out.println("Yes, the number is " + number);
else if (guess > number)
System.out.println("Your guess is too high");
else
System.out.println("Your guess is too low");
} // End of loop
}
}