I have initiated the variable 'answer' in the near header of the class.
Later on when, a random number within an entered range has been generated, that same variable gets a new different value (due to the random generator). But as you can see, the variable 'answer' is indicated in two different colors (blue vs light brown), and as you expect, the routines that I have made are therefore not working. Somehow answer is not equal to answer. What did I do wrongly???? (unfortunately here you don't see the difference in colors).
In eclipse the color of 'answer' at the very top static int answer = 0; is BLUE.
But the one int answer = ThreadLocalRandom.current().nextInt(1, userinput); is GREY
Here's my code:
package Package1;
import java.util.concurrent.ThreadLocalRandom;
import java.util.Scanner;
public class test6KOPIE
{
static int numberofattempts = 0;
static int maxnummerofattemptsallowed = 5;
static int answer = 0;
public static void main(String[] args)
{
if (answer == 0)
{
Scanner maxinput = new Scanner(System.in);
System.out.println("Under which number do you want to guess");
int userinput = maxinput.nextInt();
int answer = ThreadLocalRandom.current().nextInt(1, userinput);
System.out.println(answer);
main(args);
}
else if (numberofattempts < maxnummerofattemptsallowed)
{
Scanner higherlower = new Scanner(System.in);
System.out.println("Higher or Lower");
int digit = higherlower.nextInt();
if (answer == digit)
{
System.out.println("very well");
}
else {
if (answer > digit )
{
++numberofattempts;
System.out.println("Higher, you have " +(maxnummerofattemptsallowed - numberofattempts)+" attempt(s) left)");
System.out.println(numberofattempts);
main(args);
}
else
{
++numberofattempts;
System.out.println("Lower, you have " +(maxnummerofattemptsallowed - numberofattempts)+" attempt(s) left)");
main(args);
}
}
higherlower.close();
}
else {
System.out.println("Maximum number of attempts used, the answer was" +answer);
}
}
This is because you are re-initializing your answer variable by retyping int before it. If you simply want to reassign the value, the line should be:
answer=ThreadLocalRandom.current().nextInt(1, userinput);
Related
Im struggling with that code.
how can I use string with yes/no on that question: n1>n2, n1<n2.
the operators also need to change.
import java.util.Scanner;
import java.util.Random;
public class s {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
Random r = new Random();
int n1 = r.nextInt(10) + 1;
int n2 = r.nextInt(10) + 1;
int max = Math.max(n1, n2);
System.out.println("What is higher: "+n1+" or "+n2+" ");
int result = s.nextInt();
if(result==max)
System.out.println("Well done");
else
System.out.println("Wrong answer");
}
}
I tried a way to not use a lot of IF’S by splitting the two possible cases and not having many repeated coding lines.
By avoiding this situation, I started creating: random numbers, the random operator “>” or “<” and a boolean variable which value depends on the answer of the user.
Then I defined a variable called “reality” that will provide the correct answer, referring to which number is bigger or smaller than the other.
Finally, the program verifies if the answer of the user is the same to the reality printing the expected answer.
public static void main(String[] args) {
int bol_op= (int) Math.random()>0.5?1:0;
String operator= bol_op==1?">":"<";
int num1=(int) (Math.random()*100+1);
int num2=(int) (Math.random()*222+1);
String str_num1=num1+"";
String str_num2=num2+"";
Scanner sc= new Scanner(System.in);
System.out.println("********Logic Program**********");
System.out.println("Question: "+str_num1+operator+str_num2);
System.out.print("Answer (yes/no): ");
String answer =sc.nextLine().toLowerCase();
boolean value=false;
if(answer.equals("yes")){
value=true;
}
boolean reality=num1>num2?true:false;
if(bol_op==0){
reality=num1<num2?true:false;
}
if(reality==value){
System.out.println("Well done");
}
else{
System.out.println("Wrong answer");
}
}
Please help I cannot run this block of code:
import java.util.Scanner;
public class Methods_in_java {
public static void main(String[] args) {
boolean gameover = true;
int score = 5000;
int Levelcomplete = 5;
int bonus = 100;
boolean prize = true;
System.out.println("Please enter your name");
Scanner lic = new Scanner(System.in);
String ab = lic.nextLine();
char fir = Character.toUpperCase(ab.charAt(1));
if(fir == 'A'){
prize = true;
}
Calculatescore(gameover,score,Levelcomplete,bonus,prize);
}
public static void Calculatescore(boolean gameover,int score,int levelcomplete,int bonus,boolean prize){
if(gameover){
int finalscore = score + (levelcomplete * bonus);
if (prize){
finalscore += 1000;
}
System.out.println("Your final score is "+ finalscore);
}
}
}
charAt is zero based.
You should use ab.charAt(0) if you use only a single char.
Another good advice is to start method names with a lower case and use the camelCase format.
String ab = lic.nextLine();
char fir = Character.toUpperCase(ab.charAt(1));
Is fir supposed to be the first character in the user String? In that case you want to make sure to take zero-based indexing into account:
char fir = Character.toUpperCase(ab.charAt(0));
You have initialized your prize variable as true that will remain always true even its meet if condition or not just change it to false.
and as you were accessing the String's 2nd character using charAt(1), the index starts from 0 and if you try using charAt(0) then you will access 1st character.
Just change your code to:
public class cn {
public static void main(String[] args) {
boolean gameover = true;
int score = 5000;
int Levelcomplete = 5;
int bonus = 100;
boolean prize=false;
System.out.println("Please enter your name");
Scanner lic = new Scanner(System.in);
String ab = lic.nextLine();
char fir = Character.toUpperCase(ab.charAt(0));
if(fir == 'A'){
prize = true;
}
Calculatescore(gameover,score,Levelcomplete,bonus,prize);
}
public static void Calculatescore(boolean gameover,int score,int levelcomplete,int bonus,boolean prize){
if(gameover){
int finalscore = score + (levelcomplete * bonus);
if (prize){
finalscore += 1000;
}
System.out.println("Your final score is "+ finalscore);
}
}
}
It would be helpful if you elaborated more on what your problem is,
do you have a run time error, a compile time error, or it the output just not what you'd expect.
Your problem may be that arrays start at 0 so the first letter is charAt(0).
Actually I believe another user mentioned that the prize variable was initialized to true. I believe that that is the issue and that answer should be marked correct.
I'm trying to make this code print out the number of games played (gameNum). Instead, it always sets gameNum to 2, and prints out the last println the number of times that the game was played. I feel like I made a dumb mistake here, but I am having trouble finding it. Could you please give me a hint instead of the answer? I'd like to figure this out on my own. If not, then feel free to go ahead and write the answer.
Thanks!
import java.util.*;
public class Testing_gameNum {
public static final int amt = 1;
public static void main(String[] args) {
Scanner console = new Scanner(System.in);
guessCounter(console);
}
public static int game(Scanner console) {
Random rand = new Random();
int guess = 0;
int guessNum = 0;
System.out.printf("I'm thinking of a number...", amt);
System.out.println();
int num = 1;
do {
System.out.println("Your guess? ");
guess = console.nextInt();
guessNum += guessNum;
} while (guess != num);
return guessNum;
}
public static void guessCounter(Scanner console) {
int gameNum = 1;
int guessNum = game(console);
if (guessNum == 1){
System.out.printf("You won in %d guesses!", guessNum);
System.out.println();
}
gameNum = gameNum + 1;
System.out.println("Do you want to play again?");
String play = console.next();
if (play.equals("y")) {
guessCounter(console);
}
System.out.println("Number of games: " + gameNum);
}
}
Try something like this:
public class Testing_gameNum
{
public static final int amt = 1;
public static void main(String[] args)
{
Scanner console = new Scanner(System.in);
guessCounter(console);
}
public static int game(Scanner console)
{
Random rand = new Random();
int guess = 0;
int guessNum = 0;
System.out.printf("I'm thinking of a number...", amt);
System.out.println();
int num = 1;
do
{
System.out.println("Your guess? ");
guess = console.nextInt();
guessNum += amt;
}
while (guess != num);
return guessNum;
}
public static void guessCounter(Scanner console)
{
int gameNum = 1;
do
{
int guessNum = game(console);
if (guessNum == 1)
{
System.out.printf("You won in %d guesses!", guessNum);
System.out.println();
}
gameNum = gameNum + 1;
System.out.println("Do you want to play again?");
String play = console.next();
}
while (play.equals("y"))
System.out.println("Number of games: " + gameNum);
}
}
Check for every place gameNum is used. I found it i.e. in the method guessCounter(Scanner console) - and only there.
So every time you call this method, the value of gameNum is initialized to 1. After the game is won, you increment it by 1 and later on print it, hence the 2 in the output.
Move int gameNum = 1; out of the method guessCounter(Scanner console). This should help.
Aside of this please review also the code block
if (play.equals("y")) {
guessCounter(console);
}
Imagine a player goes on and on, always selecting "y". With every game round, you create another level of recursion. This "do you want to play again" could be implemented by a do-while loop, this will avoid the recursion.
You've defined guessCounter to be a recursive method, but that's probably not what you want for several reasons. First, each time you call guessCounter, you're creating a new gameNum and setting it to 1. You play the game and increment it to 2, but then recurse and never touch that variable again, which is the cause of your bug. Additionally, (although this is unlikely to happen in usual play), you could overflow your stack if you play the game enough times. Each time you play the game, the computer needs to remember the point in code that it needs to return to when it completes that call of guessCounter. Eventually you will run out of memory to store those pointers. Recursion is good for certain problems, but it's better to use loops most of the time.
How about using a loop rather than recursion.
I solved my question! Here's the code (explanation below):
public class Testing_gameNum {
public static final int amt = 1;
public static void main(String[] args) {
Scanner console = new Scanner(System.in);
guessCounter(console);
}
public static int game(Scanner console) {
Random rand = new Random();
int guess = 0;
int guessNum = 0;
System.out.printf("I'm thinking of a number...", amt);
System.out.println();
int num = 1;
do {
System.out.println("Your guess? ");
guess = console.nextInt();
guessNum ++;
} while (guess != num);
return guessNum;
}
public static void guessCounter(Scanner console) {
int gameNum = 0;
String play = "y";
do {
int guessNum = game(console);
gameNum += 1;
if (guessNum == 1) {
System.out.printf("You won in %d guesses!", guessNum);
System.out.println();
}
System.out.println("Do you want to play again?");
play = console.next();
} while (play.equals("y"));
System.out.println("Number of games: " + gameNum);
}
}
MY PROBLEMS: gameNum was resetting each time I called guessCounter. I needed a do/while loop; that way, I could initialize gameNum inside the method, and then loop only the section of the method that needed to be repeated. The repetitive println was linked with that same issue: it was reprinted each time I called guessCounter, as opposed to just the part of the code I wanted repeated.
Thanks for your help, everyone!
This question already has answers here:
Examples of Recursive functions [closed]
(22 answers)
Closed 5 years ago.
I am a student currently using java and I am having a hard time programming a high and low guessing game. I cannot use looping or "while" code. Any thoughts? This is what I have as of now:
public class FinalProject1
{
public static void main(String [] args)
{
System.out.println("Number Guessing Game 1-1000\nGuess a number");
guess();
}
public static int random()
{
int x = (int)(1000*Math.random() + 1);
return x;
}
public static void guess()
{
int num = random();
int tries = 0;
Scanner keyboard = new Scanner(System.in);
String inputString = keyboard.nextLine();
int input = Integer.parseInt(inputString);
if (input > num)
{
System.out.println("Guess a higher number");
inputString = keyboard.nextLine();
}
else if (input < num)
{
System.out.println("Guess a lower number");
inputString = keyboard.nextLine();
}
else if (num == input)
{
System.out.println("You Win");
}
}
}
A few things..
Your > & < checks for higher and lower are backwards
You need to be using recursion in order to produce your intended behavior without any loops.
public static void main(String [] args)
{
System.out.println("Number Guessing Game 1-1000\nGuess a number");
int num = random();
Scanner keyboard = new Scanner(System.in);
guess(keyboard, num);
}
public static int random()
{
int x = (int)(1000*Math.random() + 1);
return x;
}
public static void guess(Scanner keyboard, int goal)
{
String inputString = keyboard.nextLine();
int input = Integer.parseInt(inputString);
if (input < goal)
{
System.out.println("Guess a higher number");
guess(keyboard, goal);
}
else if (input > goal)
{
System.out.println("Guess a lower number");
guess(keyboard, goal);
}
else if (input == goal)
{
System.out.println("You Win");
}
}
Basically what's happening is that we are getting their response and checking if it's > or < the result, telling them, and the immediately calling the guess() method again in order to repeat this process until they get it right.
Wrapping your head around recursion can be fairly difficult in the beginning, just keep practicing
First, your logic is flawed. If input > num then user guessed too high, and needs to guess a lower number.
Others have suggested to use recursion, and that's the common solution for your problem, and is likely what you need to do, since you likely have just learned about recursion.
But, since I like to be contrary, I'd do it by starting a new thread, like this:
public class FinalProject1 implements Runnable {
private Scanner keyboard = new Scanner(System.in);
private int num = random();
public static void main(String[] args) {
System.out.println("Number Guessing Game 1-1000\nGuess a number");
new Thread(new FinalProject1()).start();
}
public static int random() {
return (int) (1000 * Math.random() + 1);
}
#Override
public void run() {
String inputString = this.keyboard.nextLine();
int input = Integer.parseInt(inputString);
if (input > this.num) {
System.out.println("Guess a lower number");
new Thread(this).start();
} else if (input < this.num) {
System.out.println("Guess a higher number");
new Thread(this).start();
} else if (this.num == input) {
System.out.println("You Win");
}
}
}
i'm learning Java with the book think Java : how to think like a computer scientist ? and there is no exercise answers in the book, usually i end up finding similar exercices on different websites but not for this one because i have precise instructions. Can you please tell me if it's correct.
I think the problem is solved, the job is done, but is there an easier way to do it ?
Thanks a lot
Exercise 5-7.
Now that we have conditional statements, we can get back to the “Guess My Number” game from Exercise 3-4.
You should already have a program that chooses a random number, prompts the user to guess it, and displays the difference between the guess and the chosen number.
Adding a small amount of code at a time, and testing as you go, modify the program so it tells the user whether the guess is too high or too low, and then prompts the user for another guess.
The program should continue until the user gets it right. Hint: Use two methods,
and make one of them recursive.
import java.util.Random;
import java.util.Scanner;
public class GuessStarter {
public static void Lower(int number,int number2) {
Scanner in = new Scanner(System.in);
System.out.print("Too Low , try again ");
number2 = in.nextInt();
if (number2==number) {
System.out.println("You're right");}
else if (number2>number)
Higher(number,number2);
else
Lower(number,number2); }
public static void Higher(int number,int number2) {
Scanner in = new Scanner(System.in);
System.out.print("Too high , try again ");
number2 = in.nextInt();
if (number2==number) {
System.out.println("You're right");}
else if (number2>number)
Higher(number,number2);
else
Lower(number,number2); }
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
Random random = new Random();
int number = random.nextInt(100) + 1;
int number2;
System.out.print("Type a number: ");
number2 = in.nextInt();
if (number2==number) {
System.out.println("You're right");}
else if (number2>number)
Higher(number,number2);
else
Lower(number,number2);}
}
Don't know if it'll be useful now or not, but, as I was solving the same solution, thought of letting it know if someone finds it useful:
import java.util.Random;
import java.util.Scanner;
/**
* Created by RajU on 27-Jun-17.
*/
public class GuessNumber2 {
static Scanner input = new Scanner(System.in);
public static void main(String[] args) {
message("I'm thinking of a number between 1 and 10 (including both).\n" +
"Can you guess what it is?\n" +
"Type a number: ");
int userNumber = input.nextInt();
tryAgain(userNumber, calculateRandom(10));
}
public static int calculateRandom(int n) {
Random random = new Random();
return random.nextInt(n) + 1;
}
public static void tryAgain(int userNumber, int generateRandom) {
if (userNumber == generateRandom) {
message("You're absolutely right!");
} else {
if (userNumber > generateRandom) {
message("Think of a lesser number: ");
} else {
message("Think of a greater number: ");
}
userNumber = input.nextInt();
tryAgain(userNumber, generateRandom);
}
}
public static void message(String m) {
System.out.print(m);
}
}
I just completed this exercise. It's pretty interesting to see some different approaches! Here's my take on it:
import java.util.Random;
import java.util.Scanner;
public class GuessGameLevelUp {
/*
* A guessing game where you try to guess a random number between and including 1 and 100.
* This version allows you to continue guessing until you get the right answer.
* When you're off, a hint will let yet know whether your most recent guess was too high or low.
*/
public static void main (String [] args) {
//Generates a random number for the game
Random random = new Random();
int answer = random.nextInt(100) +1;
//Introduces the game and gives a prompt
System.out.println("I'm thinking of a number between and including "
+ "1 and 100, can you guess which?");
System.out.print("Take a guess: ");
//Enables guess value input and parrots guess
Scanner in = new Scanner(System.in);
int guess;
guess = in.nextInt();
System.out.println("Your guess is: "+guess);
//Stacks a new class to determine the outcome of the game
tooHighTooLow(answer, guess);
}
public static void tooHighTooLow(int a, int g) {
//Triggers and parrots guess if correct
if (a==g) {
System.out.print("Correct! The number I was thinking of was: "+g);
//Triggers "Too Low" prompt and uses recursive to offer another attempt
} else if (a>g) {
System.out.print("Too Low! Try again: ");
Scanner in = new Scanner(System.in);
g = in.nextInt();
System.out.println("Your guess is: "+g); //Parrots guess
tooHighTooLow(a, g);
//Triggers "Too High" prompt and uses recursive to offer another attempt
}else
System.out.print("Too high! Try again: ");
Scanner in = new Scanner(System.in);
g = in.nextInt();
System.out.println("Your guess is: "+g); //Parrots guess
tooHighTooLow(a, g);
}
}
I got stuck on this one too, but your code helped me in arriving at a solution. Here's what I came up with:
import java.util.Random;
import java.util.Scanner;
public class Ch5Ex7 {
public static void compareNumbers(int userNumber,int randomNumber) {
if(userNumber == randomNumber) {
System.out.println("You got it!");
} else if ( userNumber > randomNumber ) {
System.out.println("Too high. Guess again: ");
Scanner in = new Scanner(System.in);
userNumber = in.nextInt();
compareNumbers(userNumber, randomNumber);
} else {
System.out.print("Too low. Guess again: ");
Scanner in = new Scanner(System.in);
userNumber = in.nextInt();
compareNumbers(userNumber,randomNumber);
}
}
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
Random random = new Random();
int randomNumber = random.nextInt(100) + 1;
int userNumber;
System.out.print("Type a number: ");
userNumber = in.nextInt();
compareNumbers(userNumber, randomNumber);
}
}
Thanks for pointing me in the right direction!