Good day , my program is supposed to print out all odd numbers entered in the scanner, which it does but i would like to know how can i compare both inputs, the first number should always be less than the second number upon input. How can i allow the first input to always be less than the second number ?
package loopsassign2;
import java.util.Scanner;
/**
*
* #author whitneykenny
*/
public class LoopsAssign2 {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
int start =1;
int number ;
Scanner scanner = new Scanner(System.in);
System.out.println("Input the first Number");
number=scanner.nextInt();
System.out.println("Input the second Number");
number=scanner.nextInt();
do {
if((start%2)!=0){
System.out.print((start + " "));
}
start++;
}while (start <= number);
}
}
Maybe by using input validation when you ask for the second number. Also you are assigning the second number to the same variable that you use for the first number so it may be overwritten.
while (number2 < number1)
{
System.out.println("The second number needs to be greater than the first number")
System.out.println("Input the second Number");
number=scanner.nextInt()
}
int num1;
int num2;
boolean outcome = false;
.
.
.
while (outcome!=true) {
System.out.println("Input the second Number");
num2=scanner.nextInt();
if (num2 > num1) {
outcome = true;
} else {
System.out.println("Try again.");
}
}
This is one way of solving the problem.
Related
I'm writing a number guessing game in java.
Number guessing game is a numeric version of famous hangman, where computer picks a
number between a prespecified range and user has to guess that number.
Requirements:
User must guess a number between 0-1000 and tells the user the range of guessed
number.
User has max 10 guesses.
Every time user makes a guess, total guesses reduce by one.
Computer keeps track of all the numbers user has guessed so far and shows this
information before next guess.
If the guess is correct, game ends in a win. In case of incorrect guess, computer gives a
hint to the user. If the user guess is greater than the picked number, then client tell the
user that ‘your guess is bigger’ and in case of being smaller appropriate message is
shown.
In case of invalid guess (alphabets, symbols and repeated guesses) one warning is given
and on next warning user loses a guess
The following code is running fine but it always shows the same number after guesses number. I think its not adding the new input in the arrraylist rather the first one everytime.
import java.util.*;
import java.lang.*;
public class NumberGuess {
public static void main(String[] args) {
int tries = 10;
ArrayList<Integer> guessed = new ArrayList();
int warnings = 2;
int i = 0;
Random rand = new Random();
int random = rand.nextInt(1000);
private void StartMenu () {
System.out.println("\" Welcome to the Number guessing game!\n I am thinking of a number between 0-1000\n You have 1 warning.\n You have 1 warning.\n ------------ ");
}
public char[] ToCharacterArray (String input){
char arr[] = new char[input.length()];
arr = input.toCharArray();
return arr;
}
public boolean CheckInput ( char arr[]){
if (Character.isDigit(arr[0])) {
return true;
} else {
return false;
}
}
String input;
while (tries > 0 && warnings > 0) {
System.out.println("You have " + tries + " guesses left.");
if (tries == 10) {
System.out.println("guessed number: ");
} else {
System.out.println("guessed number: ");
for (Integer a : guessed) {
System.out.println(guessed.get(i));
}
}
System.out.println("Please guess a number:");
Scanner sc = new Scanner(System.in);
input = sc.next();
char InputString[] = ToCharacterArray(input);
if (CheckInput(InputString)) {
int intInput = Integer.parseInt(input);
guessed.add(intInput);
if (intInput > random) {
System.out.println("Your guess is greater");
}
if (intInput < random) {
System.out.println("Your guess is smaller");
}
if (intInput == random) {
System.out.println("Congrats! You win.");
System.out.println("The guessed number is: " + intInput);
tries = -1;
}
}
tries--;
}
}
}
The problem is because you iterate over the guessed numbers, and then print out the item of index i from that list. The number i at that point will always be zero, so it will always print just the first element from that list. Instead, you can just print the a, that is the element itself, after the iteration on guessed. Here is how it will look like:
System.out.println("guessed number: ");
for (Integer a : guessed) {
System.out.println(a);
}
I am very new to coding and learning JAVA. I was able to execute the below code but I am not sure how to loop this until the user matches the randomNumber. Could you please help.
My current code:
package com.arwa.basicExcercisePart1;
import java.util.Scanner;
public class RandomCheck {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
Integer randomNumber = (int) Math.floor(Math.random() * 6);
System.out.println("Enter a number from 1 to 5: ");
int number = scan.nextInt();
if (number == randomNumber) {
System.out.println("Wow, The entered number matched with the Random Number.");
} else {
System.out.println("Sorry, The number you entered did not match with the Random Number, Try Again: .");
}
}
}
You can use a while loop like so:
int number;
while((number = scan.nextInt()) != randomNumber){
System.out.println("Sorry, The number you entered did not match with the Random Number, Try Again: ");
}
System.out.println("Wow, The entered number matched with the Random Number.");
Put a loop around the code that checks the user's input against the random number.
iota's answer is correct but since Aravind is learning I'd like to suggest another more didactic answer. You can use a flag to signal that the user choose the right answer and then get out of the loop. I did this below:
public class RandomCheck {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
Integer randomNumber = (int) Math.floor(Math.random() * 6);
boolean found = false; // flag is false at beginning
while (!found) { // stay in the loop till answer is correct
System.out.println("Enter a number from 1 to 5: ");
int number = scan.nextInt();
if (number == randomNumber) {
found = true; /// will finish the loop
System.out.println("Wow, The entered number matched with the Random Number.");
} else {
System.out.println("Sorry, The number you entered did not match with the Random Number, Try Again: .");
}
}
}
}
I am making a program that will take a user's input on how many numbers he wants and determine the highest number between the given. After that the user will be prompt with a Yes or no question. If the user decides to say yes, the program will loop again and if not, the program will end. Now my question is why does it take the highest number from the previous run?
import java.util.Scanner;
public class IT_VILLAFLOR_Lab1_Prog2
{
public static void main(String[] Args){
int num=1,num2,Largest=0,max;
char YN;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the Max Number = ");
max = sc.nextInt();
for(num=1; num<=max; num++)
{
System.out.print("Enter Number " + num + ": ");
num2 = sc.nextInt();
if(Largest<num2)
{
Largest=num2;
}
else if(num==max)
{
System.out.println("The Biggest number is " + Largest );
System.out.print( "Do you want to try again? Y/N ");
YN = sc.next().charAt(0);
if(YN =='Y'|| YN =='y')
{
num=0;
System.out.print('\f');
System.out.print("Enter the Max Number " );
max = sc.nextInt();
}
else
{
System.exit(0);
}
}
}
}
}
If the user wants to continue, you are resetting num to 0. Along with this, Largest also needs to be reset to 0.
num=0;
Largest=0; //new code
By the way, you need to change the line else if(num==max) to if(num==max) . Try the test case with max of 2 and values as 12 ,23.
package w3school;
import java.util.Random;
import java.util.Scanner;
public class nyttprogram {
static void indata() {
{
Scanner determinedNumber = new Scanner(System.in);
int user, computer, number, user2;
System.out.println("Input a number from 0-10");
user = determinedNumber.nextInt();
Random random = new Random();
int randomInt = random.nextInt(10);
if (user == randomInt) {
System.out.println("You guessed the correct number!");
} else {
System.out.println("You guessed the wrong number");
System.out.println("The correct number was: " + randomInt);
}
System.out.println("Input 1 if you want to try again: ");
}
}
public static void main(String[] args) {
indata();
}
}
How do I make the class start over when user input 1 OR if the Class can start over if User inputs wrong number from the start, many thanks
How do I make the class start over when user input 1 OR if the Class can start over if User inputs wrong number from the start, many thanks
The "start over" logic based on some conditions is usually implemented with while and do/while loops.
First let's extract those conditions. We want to iterate again (start over) if:
The user's guess is wrong.
The user's guess is correct, but they input a number different than 1 when asked if they want to continue.
Since we want to run the program at least once, the natural approach would be with a do/while. This will run one iteration, then check against the conditions wanted.
Here's what it looks like:
private static void inData() {
Scanner userInputScanner = new Scanner(System.in);
Random random = new Random();
// Declare the stop/continue condition
boolean isLoopContinue;
do {
// Generate a random number
int expectedNumber = random.nextInt(10);
// Ask the user to guess a number
System.out.println("Input a number from 0-10");
int givenNumber = userInputScanner.nextInt();
if (givenNumber == expectedNumber) {
// Correct answer, check if the user wants to continue
System.out.println("You guessed the correct number!");
System.out.println("\nInput 1 if you want to try again: ");
// If they input "1", then we continue. Else we stop
isLoopContinue = userInputScanner.nextInt() == 1;
} else {
// Wrong answer, loop again
System.out.println("You guessed the wrong number");
System.out.println("The correct number was: " + expectedNumber);
isLoopContinue = true;
}
} while (isLoopContinue);
}
import java.util.Scanner;
class Main {
static Scanner userInput = new Scanner(System.in);
public static void main(String[] args) {
int testNumber = userInput.nextInt();
do{
System.out.println(newNumber * 2);
newNumber++;
}while( testNumber < 1000000);
}
}
You need to update the number after you multiply it by 2:
newNumber = newNumber * 2;
System.out.println(newNumber);
Also you are using newNumber and testNumber and newNumber doesn't appear to be defined anywhere...
}while( ***testNumber***newNumber*** < 1000000);
You need to pick one because if you are updating newNumber but comparing testNumber in your loop you will have created an infinite loop.
The code you have shown shouldn't compile unless you are leaving something out of your post.
You have the right idea with your loop, but you have multiple problems with your variables.
Your first problem is that you read in a variable from the user - testNumber, but then you are (incorrectly) manipulating a completely different variable - newNumber.
Your second problem is that you are testing the unchanged variable as your stop condition.
You probably want your loop to be something like:
do {
testNumber = testNumber * 2;
System.out.println(testNumber);
} while(testNumber < 1000000);
You can also make a recursive method for it.
public int reachMillion(int num) {
if(num<=0)
return -1; // indicating it is not possible.
if(num>=1000000) // Base Condition denoting we have reached 1 million
return num;
return reachMillion(num*2); // recursive part to multiply by 2 until we reach 1 million
}
class Main {
private static Scanner userInput = new Scanner(System.in);
public static void main(String[] args) {
int newNumber = 0;
do{
System.out.println("Enter a positive number: ");
try{
newNumber = userInput.nextInt();
}catch(Exception ignored){ }
System.out.println("");
}while(newNumber <= 0);
System.out.println("----- " + newNumber + " multiply by 2 ------");
while(newNumber <= 1_000_000){
System.out.print("2 * " + newNumber +" = ");
newNumber <<= 1;//in some compilers left shift is faster than multiply
System.out.println(newNumber);
}
}
#brso05 has done well describing what went wrong here. I'd like to offer a complete example:
import java.util.Scanner;
public class Main {
private static Scanner userInputScanner = new Scanner(System.in);
public static void main(String[] args) {
System.out.print("Please input a number: ");
int userInputNumber = userInputScanner.nextInt();
System.out.println();
int newNumber = userInputNumber;
while (newNumber < 1_000_000) {
newNumber *= 2; // Take the variable on the left, multiply it by the number on the right, and save it in the variable on the left
System.out.println(newNumber);
}
}
}
Try it online!
Beware! That code does not handle any bad user input. For instance, if you give it 0, it will loop forever, and if you give it foo, it will crash. In case you want to handle all the edge cases of user input, this will do that:
import java.util.*;
public class Main {
private static Scanner userInputScanner = new Scanner(System.in);
public static void main(String[] args) {
int userInputNumber;
//
while(true) {
System.out.print("Please input a number: ");
if (userInputScanner.hasNext()) {
// The user gave us something, but we don't know if it's a number
String rawUserInput = userInputScanner.next();
try {
userInputNumber = Integer.parseInt(rawUserInput);
// If that previous line runs, the user has given us an integer!
System.out.println();
if (userInputNumber > 0) {
// The user has given a valid number. Break out of the loop and multiply it!
break;
}
else {
// The user has given a bad number. Tell them why and ask again.
System.out.println("The number has to be greater than 0.");
}
}
catch (NumberFormatException exception) {
// The user has given us something, but it wasn't an integer
System.out.println();
System.out.println("That is not a number: " + exception.getMessage());
}
}
else {
// There is no input, so we can't do anything.
return;
}
}
// Done looping through user input
int newNumber = userInputNumber;
while (newNumber < 1_000_000) {
newNumber *= 2; // Take the variable on the left, multiply it by the number on the right, and save it in the variable on the left
System.out.println(newNumber);
}
}
}
Try it online!
There is a tricky part of do-while loops. In that type of loops, do part is executed firstly. For the example below, although the input is already bigger than 1000000, it prints 1000001.
public void doWhileLoop() {
int num = 1000001;
do {
System.out.println(num);
num *= 2;
} while (num < 1000000);
}
Therefore, it will be a good idea to use some guard-clauses (aka, if-statements) before doing something in do-while loops. Like,
public void doWhileLoop() {
int num = 1000001;
if(num >= 1000000) {
return;
}
do {
System.out.println(num);
num *= 2;
} while (num < 1000000);
}