Random() not generating random number - java

I'm trying to do roshambo (or Rock-Paper-Scissors) and have the computer output Rock, Paper, or Scissors in place of a random value from 0 to 2. However, I'm not getting random values. When the program runs it goes through a while loop, and each time it goes through the loop, the value remains the same. However, if I stop, then re-run the application, the value changes, and remains that same value for the duration of the loop. Am I coding this method correctly?
public class Player2 extends Player{
private Random rand;
public Player2(){
rand = new Random();
}
public Roshambo generateRoshambo() {
int min = 0;
int max = 2;
int randomNum = rand.nextInt(max - min + 1) + min;
if(randomNum == 0){
return Roshambo.ROCK;
} else if (randomNum == 1) {
return Roshambo.PAPER;
} else {
return Roshambo.SCISSORS;
}
}
}
Here is the loop:
Roshambo value = p2.generateRoshambo();
String cont = "Yes";
do{
System.out.print("\nRock, Paper, or Scissors: ");
String choice = sc.nextLine();
System.out.println("\n" + name + ": " + choice);
System.out.println("Computer: " + value);
if (value == ...)
{
System.out.println("\n" + name + " Wins!\n");
}
else if (value == ...)
{
System.out.println("\nYou Tied!\n");
}
else
{
System.out.println("\nThe Computer Wins!\n");
}
System.out.print("Play again? (Yes/No): ");
cont = sc.nextLine();
} while (cont.equalsIgnoreCase("Yes"));

I just realized my own mistake. I called p2.generateRoshambo() outside of my do-while loop. By putting the following in my loop, I was able to solve the problem:
Roshambo value = p2.generateRoshambo()

The most likely cause of the symptom is creating a new Random instance each time round. The default seed is based on a clock that may not have ticked in a tight loop. It is important to create as few Random instances a possible, usually only one in a program, and go on getting values from it.

Related

Guessing Game, loop error

I'm having a problem with the following code for a guessing game, range set for 1-32. It starts up, but once I take my first guess, I'm given either Too High or Too Low,plus the correct answer. So I'm always able to get the correct answer in 2 guesses, which isn't suppose to happen. I think I have a problem with the while loop.
import java.util.Scanner;
import java.util.Random;
public class GuessingGame1 {
public static void main(String[] args) {
/*
* Following should create a random number
* Generated by computer between 0-32
*/
Random rng = new Random ();
int value = rng.nextInt(32);
int numberOfTries = 0;
Scanner input = new Scanner (System.in);
int guess = 0;
boolean win = false;
while (win == false) {
System.out.println("Guess of a Number between 1-32, I will tell you \n " +
"if your guess is too high, too low, or correct!");
/*
* Uses makes a guess and program tells if the guess is correct,
* too high, or too low.
*/
System.out.println("Enter your guess: ");
guess = input.nextInt();
numberOfTries++;
if (guess == value){
win = true;
} else if (guess > value){
System.out.println("Your guess is too high, try again");
} else if (guess < value){
System.out.println("Your guess is too low, try again");
}
System.out.println("Yes, the number is " + value);
System.out.println("It took you " + numberOfTries + " tries");
}
}
}
Move
System.out.println("Yes, the number is " + value);
System.out.println("It took you " + numberOfTries + " tries");
into your condition here:
if (guess == value){
win = true;
}
Otherwise, it will be called unconditionally - meaning in every iteration of the loop. Alternatively, you can print it after your while loop, as the game is finished there.

Issue with Java Guessing Game

I'm working on this guessing game for school. I've realized that at some point I deleted my while loop for the user's guess equalling the computer's random number and it has messed up the results of my program. I thought that I could just add a nested while loop, but that hasn't worked. I've been trying to figure this out for hours.
Any ideas how to add something like while (guess == number) to my code and keep it working?
/*
Programming Assignment #3: Guess
Peter Harmazinski
Week 8
Guessing Game
*/
import java.util.*;
public class Guess {
public static final int RANGE = 100;
public static void main(String[] args) {
Scanner console = new Scanner(System.in);
boolean again = true;
double guessesDividedByGames = 0;
int maxGuesses = 0;
int numGames = 0;
int numGuesses = 1;
int totalGuesses = 0;
Random rand = new Random();
int number = rand.nextInt(RANGE) + 1;
int guessTracker = 0;
while(again) {
getInstructions();
int guess = getGuess(console);
numGuesses = getHigherLower(guess, number, console);
totalGuesses += numGuesses;
again = playAgain(numGuesses, console);
numGames++;
if (numGuesses > maxGuesses) {
maxGuesses = numGuesses;
}
}
guessesDividedByGames = (double)totalGuesses / numGames;
getResults(numGames, totalGuesses, guessesDividedByGames, maxGuesses);
}
//Prints instructions for user
public static void getInstructions() {
System.out.println("This program allows you to play a guessing game");
System.out.println("I will think of a number between 1 and " + RANGE);
System.out.println("and will allow you to guess until you get it.");
System.out.println("For each guess, I will tell you whether the");
System.out.println("right answer is higher or lower than your guess");
System.out.println("");
}
//Allows the user to play again if first letter of input is "y" or "Y"
public static boolean playAgain(int guessesNum, Scanner console) {
boolean anotherTime = false;
System.out.println("You got it right in " + guessesNum + " guesses.");
System.out.println("");
System.out.print("Do you want to play again? ");
String repeat = console.next();
String[] yesOrNo = repeat.split("");
System.out.println("");
if (yesOrNo[0].equals("y") || yesOrNo[0].equals("Y")) {
anotherTime = true;
}
return anotherTime;
}
//Outputs the results if the user doesn't play again
public static void getResults(int gamesTotal, int guessesTotal, double guessesDividedByGames, int guessesMax) {
System.out.println("Overall results:");
System.out.println("\ttotal games\t= " + gamesTotal);
System.out.println("\ttotal guesses\t= " + guessesTotal);
System.out.println("\tguesses/game\t= " + guessesDividedByGames);
System.out.println("\tmax guesses\t= " + guessesMax);
}
//Tells the user whether the random number is higher or lower
//and then returns the number of guesses
public static int getHigherLower(int guess, int randomNumber, Scanner console) {
int guessIncreaser = 1;
while (guess > randomNumber) {
System.out.println("lower");
guess = getGuess(console);
guessIncreaser++;
}
while (guess < randomNumber) {
System.out.println("higher");
guess = getGuess(console);
guessIncreaser++;
}
return guessIncreaser;
}
//Asks the user to guess the random number
//then returns the guess
public static int getGuess(Scanner console) {
System.out.println("I'm thinking of a number...");
System.out.print("Your Guess? ");
int playerGuess = console.nextInt();
while (playerGuess < 1 || playerGuess > RANGE) {
System.out.println("Out of range, please try again.");
System.out.print("Your Guess? ");
playerGuess = console.nextInt();
}
return playerGuess;
}
}
The problem appears to be your getHigherLower method, specifically these two while blocks:
while (guess > randomNumber) {
System.out.println("lower");
guess = getGuess(console);
guessIncreaser++;
}
while (guess < randomNumber) {
System.out.println("higher");
guess = getGuess(console);
guessIncreaser++;
}
If the user guessed a number lower than randomNumber, then higher, both while blocks would be escaped. Instead, what you want is this:
while (guess != randomNumber) {
if (guess > randomNumber) {
System.out.println("lower");
}
else {
System.out.println("higher");
}
guess = getGuess(console);
guessIncreaser++;
}
What you need is one big while loop not two little ones
while (guess != randomNumber) {
if (guess > randomNumber) {
System.out.println("lower");
} else {
System.out.println("higher");
}
guess = getGuess(console);
guessIncreaser++;
}
First off, I'm hesitant to just give you the answer in code since this is for a school project and we learn by challenging ourselves and actualizing solutions. But I'm willing to point you in the right direction.
1. getHigherLower()
As others have pointed out, your two while loops are set up to cause errors. For instance, if I first guess too low, and then too high, your method mistakenly tells me I guessed correctly. This is a big problem!
Random number = 63
Guess 1 = 34 (lower)
Guess 2 = 100 (higher)
Actually your program tells me my guess of "100" when the number is "63" is correct!
// 1st conditional check: 34 !> 63, so skips first while loop
while (guess > randomNumber) {
guess = getGuess(console);
}
// 1st conditional check: 34 < 63, so enters second while loop
// 2nd conditional check: 100 !< 63, so skips second while loop
while (guess < randomNumber) {
// guess now becomes 100, goes back to top of while loop to check condition again
guess = getGuess(console);
}
// returns and exits method here (program wrongly thinks user has guessed correctly!)
Note that you can do a
System.out.println("random number: " + number);
to test that you're actually guessing the random number correctly. You might look into some JUnit testing as well.
James Ko seems to have a good feel for a better method implementation.
2. playAgain()
You use an if statement to check if the first index in an array of strings equals "y" or "Y" but your program never continues. Why is this?
if (yesOrNo[?].equals("y") {
anotherTime = true;
}
You should consider whether user input is really being placed at the first index or not?
Hint: loop through the "yesOrNo" array and print out each index to see where the user input is being placed in the array.
for (int i = 0; i < yesOrNo.length; i++) {
System.out.println("String at index " + i + ": " + yesOrNo[i]);
}
Good luck and remember that testing is your friend!

How to make int counter go down when answer is wrong

Im making a player 2 guesses player 1's number game. Ive made an int counter thats == 10 and is meant to go down everytime player 2 gets answer wrong. I cant get it to work and i need help on how to make this. Youll see what i mean...
package guessMain;
import java.awt.*;
import java.util.Scanner;
public class GuessCodeSource {
public static void main(String[] args){
System.out.println("WELCOME TO GUESSING GAME BY JOSH!");
System.out.println("Rules: Player 1 picks number between 1 - 100 while Player 2 has 10 tries to guess");
Scanner josh = new Scanner(System.in);
System.out.println("Enter name here PLAYER 1: ");
String p1 = josh.nextLine();
System.out.println("Enter name here PLAYER 2: ");
String p2 = josh.nextLine();
System.out.println("Ok, " + p2 + " look away. " + p1 + ", Please enter a number and press enter:");
int answer = josh.nextInt();
if (answer >= 100){
System.out.println("BUSTED! I said a number between 1 - 100!");
}else if (answer <= 100){
System.out.println("Guess in the space below.");
int guess = josh.nextInt();
if (guess == answer){
System.out.println("CORRECT!!!!!");
}else if (guess != answer);
for (int counter = 10; counter-=1);
System.out.println("You have " + count + " of guesses left");
}
}
}
To make reduce a number by one, use the decrement operator.
For example,
counter--;
would subtract one from the counter.
If you want to subtract more than one, you can use the "-=" operator in the following manner:
counter -= 2;
So, in your code, in the final else if block, you could change the code to the following to reduce "counter" by 1.
else if (guess != answer) {
counter--;
System.out.println("You have " + count + " of guesses left");
}
But, in your code, you never declare the variable counter. Somewhere, most likely at the top of your code, you want to create this variable. To create an Integer variable you do the following:
int counter = 10;
You asked how to LOOP as well, so here it is. Read the comments to gain understanding of what the code does. If you have more questions, ask below.
public static void main(String[] args) {
System.out.println("WELCOME TO GUESSING GAME BY JOSH!");
System.out.println("Rules: Player 1 picks number between 1 - 100 while Player 2 has 10 tries to guess");
Scanner josh = new Scanner(System.in);
int guess = 0; // Create these variables up here to access them everywhere in "main"
int counter = 0;
boolean continueTheGame = true; // A boolean variable that holds ONLY either true or false
System.out.println("Enter name here PLAYER 1: ");
String p1 = josh.nextLine();
System.out.println("Enter name here PLAYER 2: ");
String p2 = josh.nextLine();
System.out.println("Ok, " + p2 + " look away. " + p1 + ", Please enter a number and press enter:");
int answer = josh.nextInt();
// A while loop will continue as long as a boolean expression is true.
// So, we create a boolean variable somewhere above called "continueTheGame"
// As long as this is true, the code INSIDE of the while loop's brackets will repeat.
// If the user has less than zero guesses left, we can set the variable to false,
// which will make the loop stop!
while (continueTheGame == true) { // The start of the while loop
if (answer >= 100) {
System.out.println("BUSTED! I said a number between 1 - 100!");
} else if (answer <= 100) {
System.out.println("Guess in the space below.");
guess = josh.nextInt();
}
if (guess == answer) {
System.out.println("CORRECT!!!!!");
} else if (guess != answer) {
counter--;
System.out.println("You have " + counter + " of guesses left");
if (counter > 0) { // If they have MORE than zero guesses left, loop again!
continueTheGame = true;
} else { // If they have zero guesses left, make it stop looping
continueTheGame = false;
}
}
}
// Once the loop ends, the code will start again here,
// because the bracket above is the final bracket of the WHILE loop
}
Okay, so here is the full functional main method you are looking for:
public static void main(String[] args){
System.out.println("WELCOME TO GUESSING GAME BY JOSH!");
System.out.println("Rules: Player 1 picks number between 1 - 100 while Player 2 has 10 tries to guess");
Scanner josh = new Scanner(System.in);
System.out.println("Enter name here PLAYER 1: ");
String p1 = josh.nextLine();
System.out.println("Enter name here PLAYER 2: ");
String p2 = josh.nextLine();
System.out.println("Ok, " + p2 + " look away. " + p1 + ", Please enter a number and press enter:");
int answer = josh.nextInt();
if (answer >= 100){
System.out.println("BUSTED! I said a number between 1 - 100!");
}else {
System.out.println("Guess in the space below.");
}
for (int count = 10; count>=0; count--) {
int guess = josh.nextInt();
if (guess == answer){
System.out.println("CORRECT!!!!!");
System.exit(0);
} else {
System.out.println("You have " + count + " of guesses left");
if (count == 0) {
System.out.println("Sorry, you lost, no more tries..");
System.exit(0);
}
}
}
josh.close();
}

How would I add "You got it right in ... guesses!"

I need to add "You got it right in ... guesses!" but I'm not exactly sure how. Can someone please explain to me how to do this in java?
I would like it to display a println at the end saying how many tries it took for the user to get the number correct.
import java.util.*;
public class prog210c
{
public static void main()
{
Scanner sc = new Scanner(System.in);
Random rn = new Random();
int randomNum = rn.nextInt(90) + 10;
System.out.println("I am thinking of a number between 1 and 100");
while (true) {
System.out.print("What do you think it is? ");
int guess = sc.nextInt();
if(guess < randomNum)
{
System.out.println("Higher--Try Again");
}
else if(guess > randomNum)
{
System.out.println("Lower--Try Again");
}
else if(guess == randomNum)
{
System.out.println("Correct!");
break;
}
else
{
System.out.println("Enter a number between 1 and 100");
}
}
//System.out.println("You got it right in " + + " guesses");
} //end main
} //end class
Just create some int variable to store your number of attempts in and increment it every time you read in a guess.
int attempts = 0;
System.out.println("I am thinking of a number between 1 and 100");
while (true) {
System.out.print("What do you think it is? ");
int guess = sc.nextInt();
attempts++;
/**
* The rest of your loop code here.
*/
}
System.out.println("You got it right in " + attempts + " guesses");
The simplest way to do this is declared a counter integer, and in your logic increment it every time the user attempts.
int guessCounter = 0;
while(true) // Also do not use an infinite while loop, have an expression that can be terminated
{
...obtain input
if(guess < randomNum)
{
...
guessCounter++;
}
else if (guess > randomNum){
....
guessCounter++;
}
System.Out.println("The number of attempts " + guessCounter);
}
You could do this by creating a variable to store the number of tries, like an int, and then add one to the int every time the user guesses, by using variable++:
public static void main(){
Scanner sc = new Scanner(System.in);
Random rn = new Random();
int tries = 0;
int randomNum = rn.nextInt(90) + 10;
System.out.println("I am thinking of a number between 1 and 100");
while(true){
System.out.print("What do you think it is? ");
int guess = sc.nextInt();
//Rest of your code here
}
System.out.println("You got it right in " + tries + " guesses");
}
and if you want to go even above and beyond, you could make it so it says You got it right in 1 guess instead of it saying You got it right in 1 guesses, if the user gets the number correct on their first try. We can do this by using the ternary Java operator, which is pretty much a compact if-statement:
String s = (tries == 1 ? "guess" : "guesses");
What this is pretty much doing is: if this is true ? do this : else do this
Now we can change the You got it right in... part of your program to say guess instead of guesses if the user guesses the number on their first try:
String s = (tries == 1 ? "guess" : "guesses");
System.out.println("You got it right in " + tries + "" + s);

How to exit interior loop and go back to main loop in java?

When I run this code, which is a menu with many different options. it consists of many loops. Some of which I have yet to make. But my issue arises when I have the user select "t" or the coin toss simulator. The loop begins but once the user enters the amount of coin flips say 4, it says 2.0 heads and 2.0 tails means 50.0% were heads
Type code letter for your choice: COIN TOSS SIMULATOR
Enter 0 to quit. How many tosses?
It shouldn't say type the letter for your choice: COIN TOSS SIMULATOR, enter 0 to quit. how many tosses?
Also when I enter 0 it says You have entered an invalid option. 't' is not a valid option. I want to Bring back the main menu!!!! what is going on????
public class toolBox {
public static void main(String[] args) {
Scanner myScanner = new Scanner(System.in);
boolean properInput = false;
int usersInput;
while (!properInput) {
System.out.println("Enter seed value:");
if (myScanner.hasNextInt()) {
usersInput = myScanner.nextInt();
properInput = true;
Random randomSeed = new Random(usersInput);
String randomNumberList = "";
for (int i = 0; i < 10; i++) {
randomNumberList += randomSeed.nextInt(80) + " ";
}
} else
{
String helloWorld = myScanner.next();
System.out.println("You have not entered an integer. '" + helloWorld + "' is not an integer");
}
}
outer:
System.out.println("===== CS302 TOOL BOX =====\nT > COIN TOSS SIMULATOR\nG > GRADE ESTIMATOR\nC > COLOR CHALLENGE\nQ > QUIT");
{
Scanner anotherScanner = new Scanner(System.in);
boolean usersSelection = false;
String c;
outer:
while (!usersSelection) {
{
System.out.print("" + "Type code letter for your choice: ");
}
if (anotherScanner.hasNext("q|Q")) {
c = anotherScanner.next();
usersSelection = true;
System.out.println("" + "" + "Good-Bye");
break;
}
if (anotherScanner.hasNext("t|T")) {
{
System.out.println("" + "COIN TOSS SIMULATOR" + "");
}
System.out.println("Enter 0 to quit. How many tosses?");
Random rand = new Random();
boolean headsOrTails;
float headsCount = 0;
float tailsCount = 0;
Scanner scanMan = new Scanner(System.in);
int numero = scanMan.nextInt();
if (numero == 0) {
break outer;
}
for (int j = 0; j < numero; j++) {
headsOrTails = rand.nextBoolean();
if (headsOrTails == true) {
headsCount++;
} else {
tailsCount++;
}
}
System.out.println(headsCount + " heads and " + tailsCount + " tails means "
+ (headsCount / (headsCount + tailsCount) * 100 + "% were heads"));
}
}
if (anotherScanner.hasNext("g|G")) // if the user were to enter either case of g, the
// program will register both and initialize the
// grade estimator.
{
c = anotherScanner.next();
usersSelection = true;
}
if (anotherScanner.hasNext("c|C"))
{
c = anotherScanner.next();
usersSelection = true;
System.out.println("Welcome to the Color Challenge!");
}
else {
String zoom = anotherScanner.next();
System.out.println("You have entered an invalid option. '" + zoom + "' is not a valid option.");
}
}
}
}
Your question is not clear, but your title suggests to me you think there is an inner and outer loop.
You don't have an inner and an outer loop.
Your indentation was really messy, but when I cleaned it up and then deleted a lot of extra lines of code, the structure of the code became clear.
Notice the following:
1) You have two loops, one on top switched on !properInput, the lower one switched on !usersSelection. There is also a for loop, but it doesn't do anything related to the code flow you are asking about.
2) You have two identical labels, one outside an anonymous block of code (see my comment in the code below), and another inside the anonymous block. In this case it doesn't affect your question, but it is definitely a problem.
My guess is that your break outer line isn't working because you are breaking out of the lower while loop.
I suggest you try fragmenting your code into functions to make the structure clearer.
while (!properInput) {
}
outer:
System.out.println("===== CS302 TOOL BOX =====\nT > COIN TOSS SIMULATOR\nG > GRADE ESTIMATOR\nC > COLOR CHALLENGE\nQ > QUIT");
{ /* begin anonymous code block */
outer:
while (!usersSelection) {
if (anotherScanner.hasNext("q|Q")) {
System.out.println("" + "" + "Good-Bye");
break;
}
if (anotherScanner.hasNext("t|T")) {
System.out.println("Enter 0 to quit. How many tosses?");
if (numero == 0) {
break outer;
}
for (int j = 0; j < numero; j++) {
}
}
}
}

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