Simple Java Guessing program. Continuing - java

I am just playing around with java and wanted to make a simple program where the user; me has to guess/type in the correct number until it's correct. What can I do so the program can keep running, printing out "Make another guess" until the user/me puts in the correct number. Maybe a boolean? I'm not sure. This is what I have so far.
import java.util.Scanner;
public class iftothemax {
public static void main(String[] args) {
int myInt = 2;
// Create Scanner object
Scanner input = new Scanner(System.in);
//Output the prompt
System.out.println("Enter a number:");
//Wait for the user to enter a number
int value = input.nextInt();
if(value == myInt) {
System.out.println("You discover me!");
}
else {
//Tell them to keep guessing
System.out.println("Not yet! You entered:" + value + " Make another guess");
input.nextInt();
}
}

You might want to use a while loop to repeat some code:
while (value != myInt) {
System.out.println("Not yet! You entered: " + value + ". Make another guess");
value = input.nextInt();
}
System.out.println("You discovered me!");

This program would do the trick:
public static void main(String [] args){
int myInt = 2;
int value = 0;
Scanner input = new Scanner(System.in);
boolean guessCorrect = false;
while(!guessCorrect){
System.out.println("Not yet! You entered:" + value + " Make another guess");
value = input.nextInt();
if(value == myInt){
guessCorrect = true
}
}
System.out.println("You discover me!");
}

Simply introduce a loop.
import java.util.Scanner;
public class iftothemax {
public static void main(String[] args) {
int myInt = 2;
// Create Scanner object
Scanner input = new Scanner(System.in);
for(;;) {
//Output the prompt
System.out.println("Enter a number:");
//Wait for the user to enter a number
int value = input.nextInt();
if(value == myInt) {
System.out.println("You discover me!");
break;
}
else {
//Tell them to keep guessing
System.out.println("Not yet! You entered:" + value + " Make another guess");
}
}
}
}

Related

NoSuchElementException error for ATM Machine app (Modified)

I am currently learning Java and I am trying to retain the information I learned by building a ATM machine app (I plan on adding more to it in the future).
My current issue is I would like to ask a user 'What would you like to do' repeatedly until a valid input is provided(current valid inputs are 'Withdraw' and 'Deposit').
I have a loop that will repeatedly ask the user 'Please select a valid choice' if the input is not valid. If the input is valid it will execute only once, ask 'What would you like to do', and then display a NoSuchElementException. Not sure how to fix this.
Here is my code:
App.java
import java.util.Scanner;
public class App {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
boolean done = false;
while(!done) {
System.out.println("What woul you like to do?");
String response = scanner.next().toLowerCase();
Transactions newTransaction = new Transactions();
if (response.equals("withdraw")) {
newTransaction.Withdrawal();
} else if (response.equals("deposit")) {
newTransaction.Deposit();
} else {
System.out.println("Please select a valid choice");
}
}
scanner.close();
}
}
Transactions.java
import java.util.Scanner;
public class Transactions {
private int currentBalance = 100;
public void Withdrawal() {
Scanner scanner = new Scanner(System.in);
System.out.println("How much would you like to withdraw?");
int withdrawAmount = scanner.nextInt();
if (withdrawAmount > 0) {
if (currentBalance > 0) {
currentBalance -= withdrawAmount;
System.out.println("Amount withdrawn: $" + withdrawAmount);
System.out.println("Current Balance: $" + Balance());
if (currentBalance < 0) {
System.out.println(
"You have withdrawn more than you have in current balance.\nYou will be charged a overdraft fee");
}
} else {
System.out.println(
"You have withdrawn more than you have in current balance.\nYou will be charged a overdraft fee");
}
} else {
System.out.println("Can't remove 0 from account");
}
scanner.close();
}
public void Deposit() {
Scanner scanner = new Scanner(System.in);
System.out.println("How much would you like to deposit?");
int depositAmount = scanner.nextInt();
if (depositAmount > 0) {
currentBalance += depositAmount;
Balance();
}
System.out.println("Amount deposited: $" + depositAmount);
System.out.println("Current Balance: $" + Balance());
scanner.close();
}
public int Balance() {
return currentBalance;
}
}
Error Message
NoSuchElementException
You can use a sentinel. A sentinel is a value entered that will end the iteration.
//incomplete code showing logic
int choice;
Scanner input = new Scanner(System.in);
System.out.println("Enter Choice");
choice = input.nextInt();
while(choice != -1){ //-1 is the sentinel, can be value you choose
//Some logic you want to do
System.out.println("Enter choice or -1 to end");
choice = input.NextInt(); //notice we input choice again here
}
Like has been said you should learn about loops. There are two types while-loop and for-loop. In this case you should youse the while-loop.
The implementation of your problem could be this.
public class App {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
System.out.println("What woul you like to do?");
String response;
Transactions newTransaction = new Transactions();
while (true) {
response = scanner.next().toLowerCase();
if (response.equals("withdraw")) {
newTransaction.Withdrawal();
break;
} else if (response.equals("deposit")) {
newTransaction.Deposit();
break;
} else {
System.out.println("Please select a valid choice");
}
}
scanner.close();
}
}

How to break else statement and exit the program

package oddsorevens;``
import java.util.Scanner;
import java.util.Random;
public class OddsOrEvens
{
public static void main(String[] args)
{
Scanner name= new Scanner (System.in); // getting input from user
System.out.print("Hi! What's your name: ");
String user = name.nextLine(); // getting user name
System.out.println("Hello: "+user);
System.out.println("Let's play OddsOrEvens");
System.out.println("Choose Odd or Even");
String s ="oddOrEven";
Scanner str = new Scanner(System.in); // getting new string from user
String s1 = str.next(); //storing odd or even here
o:
if (s1.equals("even")||(s1.startsWith("e")))
{
System.out.println("You choose even");
System.out.println("Computer choose odd");
}
else if (s1.equals("odd")||(s1.startsWith("o")))
{
System.out.println("You choose odd");
System.out.println("Computer choose even");
}
else
{
System.out.println("Entered wrong keyword");
}
System.out.print("How many fingers you want to put out: ");
Scanner num = new Scanner(System.in);
int n=num.nextInt();
Random rand = new Random();
int computer = rand.nextInt(6);
System.out.println("Computer choose "+ computer +" fingers");
int sum;
sum=n+computer;
System.out.println(sum);
if(sum%2==0)
{
System.out.println(sum+" is even");
}
else
{
System.out.println(sum+" is odd");
}
int u = s1.length();
if(u/2==0)
{
System.out.println("You won :)");
}
else
{``
System.out.println("You lose :(");
}
}
}
This is my first pgm in java. here if the user enter wrong keyword pgm should be break and based on the user input the output of the pgm will be win or lose. help please.
Whenever you want your application to stop, you have to explicitly tell that you want to exit. To do so you have write just piece of line of code and that is System.exit(0)
Here sample code to understand it better:
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
if (s.next().equals("o")) {
System.out.println("game is still on");
} else {
System.out.println("game end!");
System.exit(0);
}
}

Guessing a number

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");
}
}

same functionality but without using continue and break?

how would you restructure this code so it doesnt use continue and break? i have tried but have had no luck. thanks
import java.util.*;
public class q6 {
public static void main(String args[]) {
int Number;
Scanner sc = new Scanner(System.in);
while (true) // seemingly an infinite loop
{
System.out.print("Enter a positive integer ");
System.out.println("or 0 to exit ");
Number = sc.nextInt();
if (Number == 0)
break;
else if (Number < 0);
System.out.print("Squareroot of " + Number);
System.out.println(" = " + Math.sqrt(Number));
//continue lands here at end of current iteration
}
//break lands here
System.out.println("a zero was entered");
}
}
import java.util.*;
public class q6 {
public static void main(String args[]) {
int Number;
Scanner sc = new Scanner(System.in);
System.out.print("Enter a positive integer ");
System.out.println("or 0 to exit ");
Number = sc.nextInt();
while (Number>0)// looping while number >0
{
System.out.print("Squareroot of " + Number);
System.out.println(" = " + Math.sqrt(Number));
Number = sc.nextInt();
}
System.out.println("a zero was entered");
}
import java.util.*;
class q6 {
public static void main(String args[]) {
int Number;
Scanner sc = new Scanner(System.in);
while (instruct() && (Number=sc.nextInt())!=0) // seemingly an infinite loop
{
if (Number < 0);
System.out.print("Squareroot of " + Number);
System.out.println(" = " + Math.sqrt(Number));
//continue lands here at end of current iteration
}
//break lands here
System.out.println("a zero was entered");
}
static boolean instruct()
{
System.out.print("Enter a positive integer ");
System.out.println("or 0 to exit ");
return true;
}
}

How to ask user to Play Again....Guess Game

I'm making a simple guess game but I don't know how to ask the player if the want to play the game again.Everytime the game ends I have to run the game again so I want to add this feature to it.I looked in some other posts but they didn't help.Here's the code:
import java.util.*;
public class guessNumber{
private static Scanner userInput = new Scanner(System.in);
public guessNumber(){
System.out.println("~~~Guess Game~~~");
}
public void guessGame(){
System.out.println("Enter the maximum number:");
int maxNum = userInput.nextInt();
System.out.println("Guess a number between 0 and " + maxNum + ":");
int randomNumber = (int) (Math.random() * maxNum);
boolean gameOn = true;
int numberOfTries = 0;
while(gameOn){
boolean printOthers = true;
numberOfTries++;
int number = userInput.nextInt();
if(number > maxNum){
System.out.println("Please enter a number between 0 and " + maxNum + ".");
printOthers = false;
}
if(printOthers){
if(number == randomNumber){
System.out.println("=================================");
System.out.println("You guessed the right number xD.");
System.out.println("Your tried " + numberOfTries + " times.");
System.out.println("=================================");
}else if(number > randomNumber){
System.out.println("Try a lower number");
}else if(number < randomNumber){
System.out.println("Try a higher number");
}
else{
System.out.println("Please enter a number between 0 and " + maxNum + ".");
}
}
}
}
public static void main(String[] args){
guessNumber guess = new guessNumber();
guess.guessGame();
}
}
In your main use a while loop. In the loop first call your guessGame() then, similarly to how you ask to enter a number, you ask if they want to play again (Y/N ?) and if they say no you break the loop otherwise you go ahead...
Add your calling method in main method with in a while loop
public static void main(String[] args){
Scanner scanner = new Scanner(System.in);
do{
//call your game
System.out.println("Do you want to play again. Press y");
}
while(scanner.next().equals("y"));

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