I am relatively new to Java, and I am writing a simple program to play rock, paper, scissors. This is the code:
import java.util.Random;
import java.util.Scanner;
public class Main {
public static String comChoice() {
Random rand = new Random();
int num = rand.nextInt(299) + 1;
if (num >= 1 && num <= 99) {
String pick = "SCISSORS";
} else if (num >= 100 && num <= 199) {
String pick = "ROCK";
} else if (num >= 200 && num <= 299) {
String pick = "PAPER";
}
return pick;
}
public static void main(String args[]) {
int wins = 0;
int losses = 0;
int ties = 0;
while (1 == 1) {
Scanner s = new Scanner(System.in);
System.out.println("Would you like to play Rock Paper Scissors? Y/N");
String n = s.next();
if (n.equalsIgnoreCase("Y")) {
Scanner t = new Scanner(System.in);
System.out.println("Enter your pick: rock, paper, or scissors");
String userChoice = t.next();
String pick = comChoice();
if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("SCISSORS")) {
System.out.println("TIE");
ties++;
} else if (userChoice.equalsIgnoreCase("ROCK") && pick.equalsIgnoreCase("SCISSORS")) {
System.out.println("WIN");
wins++;
} else if (userChoice.equalsIgnoreCase("PAPER") && pick.equalsIgnoreCase("SCISSORS")) {
System.out.println("LOSE");
losses++;
} else if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("ROCK")) {
System.out.println("LOSE");
losses++;
} else if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("PAPER")) {
System.out.println("WIN");
wins++;
} else {
System.out.println("Enter a valid choice");
}
} else {
System.out.println("You won " + wins + " matches");
System.out.println("You tied " + ties + " matches");
System.out.println("You lost " + losses + " matches");
break;
}
}
}
}
I'm getting an error in my method which says this:
Main.java:23: error: cannot find symbol
return pick;
^
symbol: variable pick
location: class Main
1 error
exit status 1
I can't figure out how to fix this error. I would appreciate your input as well as any other general advice
Thanks
Your variable is only visible in the if statement. Read about scopes.
Change to:
import java.util.Scanner;
import java.util.Random;
public class Main {
public static String comChoice() {
Random rand = new Random();
int num = rand.nextInt(299) + 1;
String pick = null;
if (num >= 1 && num <= 99) {
pick = "SCISSORS";
} else if (num >= 100 && num <= 199) {
pick = "ROCK";
} else if (num >= 200 && num <= 299) {
pick = "PAPER";
}
return pick;
}
....
}
pick is out of scope. Try declaring at the start of the comChoice method.
Hence :
public static String comChoice() {
String pick=null;
Random rand = new Random();
int num = rand.nextInt(299) + 1;
if (num >= 1 && num <= 99) {
pick = "SCISSORS";
} else if (num >= 100 && num <= 199) {
pick = "ROCK";
} else if (num >= 200 && num <= 299) {
pick = "PAPER";
}
return pick;
}
variable pick is out of scope. You have to declare it outside the all if else statements. if all if else condition fail then comChoice method will not be able to find variable pick (as it is declared inside the if else block only)which it has to return.
corrected code
import java.util.Scanner;
import java.util.Random;
public class Main
{
public static String comChoice()
{
Random rand = new Random();
int num = rand.nextInt(299) + 1;
String pick = "";
if(num >= 1 && num <= 99)
{
pick = "SCISSORS";
}
else if (num >= 100 && num <= 199)
{
pick = "ROCK";
}
else if (num >= 200 && num <= 299)
{
pick = "PAPER";
}
return pick;
}
public static void main (String args[])
{
int wins = 0;
int losses = 0;
int ties = 0;
while (1 == 1)
{
Scanner s = new Scanner (System.in);
System.out.println("Would you like to play Rock Paper Scissors? Y/N");
String n = s.next();
if (n.equalsIgnoreCase("Y"))
{
Scanner t = new Scanner (System.in);
System.out.println("Enter your pick: rock, paper, or scissors");
String userChoice = t.next();
String pick = comChoice();
if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("SCISSORS"))
{
System.out.println("TIE");
ties++;
}
else if (userChoice.equalsIgnoreCase("ROCK") && pick.equalsIgnoreCase("SCISSORS"))
{
System.out.println("WIN");
wins++;
}
else if (userChoice.equalsIgnoreCase("PAPER") && pick.equalsIgnoreCase("SCISSORS"))
{
System.out.println("LOSE");
losses++;
}
else if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("ROCK"))
{
System.out.println("LOSE");
losses++;
}
else if (userChoice.equalsIgnoreCase("SCISSORS") && pick.equalsIgnoreCase("PAPER"))
{
System.out.println("WIN");
wins++;
}
else
{
System.out.println("Enter a valid choice");
}
}
else
{
System.out.println("You won " + wins + " matches");
System.out.println("You tied " + ties + " matches");
System.out.println("You lost " + losses + " matches");
break;
}
}
}
}
You declared your variable pick in the if else structure. Doing this causes the problem that your variable cannot be accessed from outside that if else structure. In simple words, the variable pick's scope is limited to your if else structure. You have to declare your variable (and initialize it as well, otherwise you'll get an error in your case) outside of the if else structure. Like this:
String pick = null;
if(num >= 1 && num <= 99) {
...
...
...// All your if's and else's
}
return pick;
Hope this helps!
Related
I am a new human learning to code!
I had a problem with my Scanner, which is that I need it to 'reset' on an invalid character.
My code:
public class Lemonade {
static int m = 150;
private static Scanner scan;
public static void main(String[] args) {
int day = 1;
for(int gameover = m; gameover > 0; day++) {
int Random = (int) (Math.random() * 100);
if(Random <= 25) {
System.out.println("Great Chance!");
System.out.println("--------------------------------");
}
else if(Random <= 50) {
System.out.println("Good Chance!");
System.out.println("--------------------------------");
}
else if(Random <= 75) {
System.out.println("Bad Chance!");
System.out.println("--------------------------------");
}
else if(Random <= 100) {
System.out.println("Awful Chance!");
System.out.println("--------------------------------");
}
int count = 0;
int none = 0;
scan = new Scanner(System.in);
System.out.println("Enter a number between 0 and " + m + "!");
count = scan.nextInt();
if(count >= none && count <= m) {
System.out.println("You entered " + count + "!");
System.out.println("--------------------------------");
day = day + 1;
m = m - count;
System.out.println("Day " + day);
}
else {
System.out.println("Enter a number between 0 and " + m + ".");
count = scan.nextInt();
}
}
}
}
Now is my question how to get this to 'reset' on an invalid character like 'f', as Scanner only accepts numbers.
Thanks for the help!
If I understand you correctly then this is something you're looking for,
InputMismatchException will thrown if user enters invaild characters instead of int. You may use looping until the user enters an integer
import java.util.Scanner;
import java.util.InputMismatchException;
class Example
{
public static void main(String args[])
{
boolean isProcessed = false;
Scanner input = new Scanner(System.in);
int value = 0;
while(!isProcessed)
{
try
{
value = input.nextInt();
//example we will now check for the range 0 - 150
if(value < 0 || value > 150) {
System.out.println("The value entered is either greater than 150 or may be lesser than 0");
}
else isProcessed = true; // If everything is ok, Then stop the loop
}
catch(InputMismatchException e)
{
System.out.print(e);
input.next();
}
}
}
}
If this is not you're looking for please let me know!
I have a game that's running perfectly. I want to put a line of code that asks the player if they want to play again at the end of the game. I would also like to keep a score system for every player and computer win.
I'm having trouble with the input = Integer.parseInt(sc.nextInt()); line
import java.util.Scanner;
public class Sticks {
public static boolean whoStart(String choice) {
int ran = (int) (Math.random() * 2 + 1);
String ht = "";
switch (ran) {
case 1:
ht = "head";
break;
case 2:
ht = "tails";
}
if (ht.equals(choice.toLowerCase())) {
System.out.println("you start first");
return true;
} else {
System.out.println("computer starts first");
return false;
}
}
public static int playerTurn(int numberOfSticks) {
System.out.println(" \nthere are " + numberOfSticks + " sticks ");
System.out.println("\nhow many sticks do you wanna take? 1 or 2?");
Scanner in = new Scanner(System.in);
int sticksToTake = in.nextInt();
while ((sticksToTake != 1) && (sticksToTake != 2)) {
System.out.println("\nyou can only take 1 or 2 sticks");
System.out.println("\nhow many sticks do you wanna take?");
sticksToTake = in.nextInt();
}
numberOfSticks -= sticksToTake;
return numberOfSticks;
}
public static int computerTurn(int numberOfSticks) {
int sticksToTake;
System.out.println("\nthere are " + numberOfSticks + " sticks ");
if ((numberOfSticks - 2) % 3 == 0 || (numberOfSticks - 2 == 0)) {
sticksToTake = 1;
numberOfSticks -= sticksToTake;
} else {
sticksToTake = 2;
numberOfSticks -= sticksToTake;
}
System.out.println("\ncomputer took " + sticksToTake + " stick ");
return numberOfSticks;
}
public static boolean checkWinner(int turn, int numberOfSticks) {
int score = 0;
int input;
int B = 1;
int Y=5, N=10;
if ((turn == 1) && (numberOfSticks <= 0)) {
System.out.println("player lost");
return true;
}
if ((turn == 2) && (numberOfSticks <= 0)) {
System.out.println("player won");
score++;
return true;
}
System.out.println("Your score is "+ score);
System.out.println("Do you want to play again? Press (5) for Yes / (10) for No");
// ----- This line -----
input = Integer.parseInt(sc.nextInt());
if (input == Y) {
B = 1;
System.out.println("Rock, Paper, Scissors");
} else if (input == N) {
System.exit(0);
System.out.println("Have A Good Day!");
}
}
public static void main(String args[]) {
int turn;
int numberOfSticks = 21;
Scanner in = new Scanner(System.in);
System.out.println("choose head or tails to see who starts first");
String choice = in.next();
if (whoStart(choice) == true) {
do {
turn = 1;
numberOfSticks = playerTurn(numberOfSticks);
if (checkWinner(turn, numberOfSticks) == true) {
break;
};
turn = 2;
numberOfSticks = computerTurn(numberOfSticks);
checkWinner(turn, numberOfSticks);
} while (numberOfSticks > 0);
} else {
do {
turn = 2;
numberOfSticks = computerTurn(numberOfSticks);
if (checkWinner(turn, numberOfSticks) == true) {
break;
};
turn = 1;
numberOfSticks = playerTurn(numberOfSticks);
checkWinner(turn, numberOfSticks);
} while (numberOfSticks > 0);
}
}
}
The title of your question almost answered you what you need to add: a loop!
I suggest you to refactor your function main and extract all your game logic from it to be stored within a dedicated function for the sake of the readability. Let's call it startGame().
Your main is going to become shorter and can represent a good location to introduce this loop, such as:
public static void main(String[] a) {
boolean isPlaying = true;
Scanner in = new Scanner(System.in);
while(isPlaying) {
startGame();
// Your message to continue or stop the game
if(in.next().equalsIgnoreCase("No")) {
isPlaying = false;
}
}
}
I recommend you to use a boolean that is checked in your while loop rather than using a break statement, as it brings a better control flow in your application.
Just put everything in a while(true) loop and use a break; if they choose no. Something like:
static int playerPoints = 0;
public static void main(String args[]) {
int turn;
int numberOfSticks = 21;
Scanner in = new Scanner(System.in);
while(true){
...
System.out.println("You have " + playerPoints + " points!")
System.out.println("Do you want to play again?");
if (!in.nextLine().toLowerCase().equals("yes")){
break;
}
}
}
Edit: ZenLulz's answer is better than this one, mainly because it encourages better programming practice. Mine works but isn't the best way to solve the issue.
So, I'm working on this assignment for a class. It's a Java class, and I'm supposed to make a game where it rolls two dice, adds them up, and adds them to your turn score. It then asks if you want to keep playing. When your turn score hits 20, or when you decide to pass, it goes to a computer. It's supposed to print the scores each turn, and then when someone hits 100 points, it announces the winner. However, no matter what, the score at the end of each turn is 0, no matter how many times I run it. When a player rolls a 1, their turn score is cancelled, and it moves on to the other player, and if they roll double 1's, they lose all of their points for the game so far. Here is my code, can you figure out why the score variables don't update? Thank you.
import java.util.Scanner;
import java.util.Random;
public class PlayPig {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scan = new Scanner(System.in);
int player1 = 0;
int player2 = 0;
int a, b, c, player1turn, player2turn, input;
int pig = 1;
Random r = new Random();
do{
do {
player1turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if( a==1 || b==1){
if (a == 1 && b == 1){
player1=0;
break;}
else if (a==1 || b==1){
player1turn=0;
break;}
else {
player1turn= a+b ;
}}
player1= player1+player1turn;
System.out.println("Player1 score is " + player1 + " and player2 score is " + player2);
System.out.print("Do you want to keep playing? Enter 1 to continue. Enter any other number to pass.");
input = scan.nextInt();
if (input != 1)
break;
}
while
(player1turn <= 20);
do{
player2turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if( a==1 || b==1){
if (a == 1 && b == 1){
player2=0;
break;}
else if (a==1 || b==1){
player2turn=0;
break;}
else {
player1turn= a+b ;
player2= player2+player2turn;}}
}
while
(player2turn<=20);
}
while
(player1 < 100 || player2 < 100);
if (player1>player2)
System.out.print("Player 1 wins");
else
System.out.print("Player 2 wins");
}}
The main problem was, that your else conditions in which you assigned the current score were in the wrong block. (These ones):
else {
player1turn = a+b ;
}
Try this code:
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scan = new Scanner(System.in);
int player1 = 0;
int player2 = 0;
int a, b, c, player1turn, player2turn, input;
int pig = 1;
Random r = new Random();
do{
do {
player1turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if( a==1 || b==1){
if (a == 1 && b == 1){
player1 = 0;
break;
}
else if (a==1 || b==1){
player1turn=0;
break;
}
}else {
player1turn = a+b ;
}
player1 += player1turn;
System.out.println("Player1 score is " + player1 + " and player2 score is " + player2);
System.out.print("Do you want to keep playing? Enter 1 to continue. Enter any other number to pass.");
input = scan.nextInt();
if (input != 1){
break;
}
} while (player1turn <= 20);
do{
player2turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if( a==1 || b==1){
if (a == 1 && b == 1){
player2=0;
break;
} else if (a==1 || b==1){
player2turn=0;
break;
}
}else {
player2turn = a+b ;
player2 += player2turn;
}
}while (player2turn<=20);
} while (player1 < 100 || player2 < 100);
if (player1>player2)
System.out.print("Player 1 wins");
else
System.out.print("Player 2 wins");
}
I have modified the if loop.
You can try this:
import java.util.Scanner;
import java.util.Random;
public class PlayPig {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scan = new Scanner(System.in);
int player1 = 0;
int player2 = 0;
int a, b, c, player1turn, player2turn, input;
int pig = 1;
Random r = new Random();
do{
do {
player1turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if (a == 1 && b == 1){
player1=0;
break;
}
else if((a== 1 && b!= 1) || (a!=1 && b== 1){
player1turn=0;
break;
}
else{
player1turn= a+b ;
}
player1= player1+player1turn;
System.out.println("Player1 score is " + player1 + " and player2 score is " + player2);
System.out.print("Do you want to keep playing? Enter 1 to continue. Enter any other number to pass.");
input = scan.nextInt();
if (input != 1)
break;
}
while
(player1turn <= 20);
do{
player2turn=0;
a = r.nextInt(6)+1;
b = r.nextInt(6)+1;
if (a == 1 && b == 1){
player2=0;
break;
}
else if((a== 1 && b!= 1) || (a!=1 && b== 1){
player2turn=0;
break;
}
else{
player2turn= a+b ;
}
player2= player2+player2turn;
}
while
(player2turn<=20);
}
while
(player1 < 100 || player2 < 100);
if (player1>player2)
System.out.print("Player 1 wins");
else
System.out.print("Player 2 wins");
}}
My variable names are pretty stupid near the bottom but that's not the point. Line 110 says that I'm making an else statement without the if and I'm nearly certain the if is there. Please help in any way you can.
Thank you
import java.util.*;
public class hw7
{
public static void main(String[] args)
{
int turnScores = 0;
int totalScores = 0;
int turnScores2 = 0;
int totalScores2 = 0;
int dice;
int dice2;
String input = "r";
char repeat;
boolean peppers;
peppers = true;
Scanner keyboard = new Scanner(System.in);
Random randomNumbers = new Random();
System.out.println("Welcome to the game of Pig!\n");
while(totalScores < 20 || totalScores2 < 20)
{
do
{
dice = randomNumbers.nextInt(6) + 1;
System.out.println("You rolled: " + dice);
if(dice == 1)
{
turnScores = 0;
System.out.print("Your lose your turn!");
System.out.println("Your Total is " + totalScores);
break;
}
else
{
turnScores += dice;
System.out.print("Your turn score is " + turnScores);
System.out.println(" and your total scores is " + totalScores);
System.out.println("If you hold, you will have " + turnScores
+ " points.");
System.out.println("Enter 'r' to roll again, 'h' to hold.");
input = keyboard.nextLine();
repeat = input.charAt(0);
if(repeat == 'h')
{
break;
}
}
}
while(input.equalsIgnoreCase("r") || dice != 1);
totalScores += turnScores;
peppers = peppers(turnScores, turnScores2);
System.out.println("Your scores is " + totalScores);
turnScores = 0;
System.out.println();
System.out.println("It is the computer's turn.");
do
{
dice2 = randomNumbers.nextInt(6) + 1;
System.out.println("The computer rolled: " + dice2);
if(dice2 == 1)
{
turnScores2 = 0;
System.out.print("The computer lost its turn!");
System.out.println(" Computer total is " + totalScores2);
break;
}
else
{
turnScores2 += dice2;
if(turnScores2 >= 20 || (totalScores2 + turnScores2) >= 20 )
{
System.out.println("The computer holds");
break;
}
}
}
while(dice2 != 1 || turnScores2 < 20);
totalScores2 += turnScores2;
System.out.println("The computer's scores is " + totalScores2 + "\n");
turnScores2 = 0;
}
}
public static boolean peppers(int chili, int ghost)
{
boolean done;
done = true;
if(chili >= 20);
{
done = false;
System.out.println(" YOU WIN!!!");
return done;
}
else (ghost >= 20);
{
done = false;
System.out.println(" COMPUTER WINS");
return done;
}
/*else
{
return done;
}
*/
}
}
Try removing the semicolons in if(chili >= 20); and else (ghost >= 20);.
public static boolean peppers(int chili, int ghost)
{
boolean done;
done = true;
if(chili >= 20)
{
done = false;
System.out.println(" YOU WIN!!!");
}
else if (ghost >= 20)
{
System.out.println(" COMPUTER WINS");
}
return done;
}
replace
else (ghost >= 20);
with
else if (ghost >= 20)
and remove the semicolons after the if-statement.
What I really am stuck with is the second to last variable userGuessDifference. It remains at zero making my second while loop not run properly as it just keeps going back to the first else if statement.
public class GuessingGame {
/**
* #param args
*/
public static void main(String[] args)
{
Scanner keyboard = new Scanner (System.in);
Random generator = new Random();
int difficulty = 0;
int guesses = 0;
int userGuess = 0;
int correctAnswer = 0;
int counter = 0;
int userGuessDifference = (Math.abs(correctAnswer) - Math.abs(userGuess));
boolean flag = false;
System.out.println("We are going to play a number guessing game.");
System.out.println(" ");
System.out.println("Choose your difficulty:");
System.out.println("Pick a number - 10 is easy, 25 is medium, 50 is hard.");
difficulty = keyboard.nextInt();
if (difficulty == 10)
{
guesses = 3;
System.out.println("You have 3 guesses, make them count!");
}
else if (difficulty == 25)
{
guesses = 5;
System.out.println("You have 5 guesses, make them count!");
}
else if (difficulty == 50)
{
guesses = 6;
System.out.println("You have 6 guesses, make them count!");
}
else
{
System.out.println("If you can't follow instructions, I'm going to make this very difficult for you!");
difficulty = (difficulty * 100);
guesses = 1;
}
System.out.println(" ");
System.out.println("Ok, I have my number. Time to play.");
correctAnswer = generator.nextInt(difficulty) + 1;
System.out.println("Pick a whole number between 1 and " + difficulty + ":");
userGuess = keyboard.nextInt();
while (!flag || (counter <= guesses))
{
if (userGuess == correctAnswer)
{
System.out.println("CONGRATS YOU WIN!");
flag = true;
}
else if ((userGuessDifference <= (difficulty * .10)))
{
System.out.println("HOT!");
userGuess = keyboard.nextInt();
counter++;
}
else if ((userGuessDifference < (difficulty * .25)) && (userGuessDifference > (difficulty * .10)))
{
System.out.println("Warm...");
userGuess = keyboard.nextInt();
counter++;
}
else
{
System.out.println("Ice cold.");
userGuess = keyboard.nextInt();
counter++;
}
}
}
}
As #SotiriosDelimanolis wrote, you never reassign userGuessDifference. This should be done inside the while loop.
Moreover, there is another problem with your code: if you guess the number, the program just prints "CONGRATS YOU WIN!" forever, but it seems to me that you wanted to quit from the while loop once the user guesses the number (I guess the flag variable was introduced for this reason).
I slightly changed your code in order to meet this requirement:
import java.util.Random;
import java.util.Scanner;
public class GuessingGame {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
Random generator = new Random();
int difficulty = 0;
int guesses = 0;
int userGuess = 0;
int correctAnswer = 0;
int counter = 0;
System.out.println("We are going to play a number guessing game.");
System.out.println(" ");
System.out.println("Choose your difficulty:");
System.out.println("Pick a number - 10 is easy, 25 is medium, 50 is hard.");
difficulty = keyboard.nextInt();
if (difficulty == 10) {
guesses = 3;
System.out.println("You have 3 guesses, make them count!");
} else if (difficulty == 25) {
guesses = 5;
System.out.println("You have 5 guesses, make them count!");
} else if (difficulty == 50) {
guesses = 6;
System.out.println("You have 6 guesses, make them count!");
} else {
System.out.println("If you can't follow instructions, I'm going to make this very difficult for you!");
difficulty = (difficulty * 100);
guesses = 1;
}
System.out.println(" ");
System.out.println("Ok, I have my number. Time to play.");
correctAnswer = generator.nextInt(difficulty) + 1;
System.out.println("Pick a whole number between 1 and " + difficulty + ":");
userGuess = keyboard.nextInt();
while (counter <= guesses) {
// int userGuessDifference = (Math.abs(correctAnswer) - Math
// .abs(userGuess));
int userGuessDifference = Math.abs(correctAnswer - userGuess);
if (userGuess == correctAnswer) {
System.out.println("CONGRATS YOU WIN!");
break;
}
else if ((userGuessDifference <= (difficulty * .10))) {
System.out.println("HOT!");
}
else if ((userGuessDifference < (difficulty * .25))
&& (userGuessDifference > (difficulty * .10))) {
System.out.println("Warm...");
}
else {
System.out.println("Ice cold.");
}
userGuess = keyboard.nextInt();
counter++;
}
}
}