程序忽略“ If else”并打印所有内容

Question

I'm trying to create a Random Number Generator program which tracks a player's wins, losses, winning percentage and total winnings. The logic of the program is that a player gets 3 chances per session and the computer generates a random number which the player needs to guess or rather should match.

I've tried to use if & else statements to tell the user if he needs to guess a higher number or a lower number within the 3 allowed guesses. What's happening is that it completely ignores the conditions and prints all three chances at once and ends the game.

Any inputs on this would be highly appreciated.

Game Class:

import java.util.Scanner;

public class Game {

    Player player;
    LuckyNumberGenerator lng;

    public Game() {
        player = new Player();
        lng = new LuckyNumberGenerator();
    }

    public void eventLoop() {
        Scanner scanner = new Scanner(System.in);
        int choice = 0;
        boolean exit = false;
        while (!exit) {
            System.out.println("Welcome to the Guessing Game");
            System.out.println("==============================");
            System.out.println("(1) Set Up New Player");
            System.out.println("(2) Play One Round");
            System.out.println("(3) Player Win Statistics");
            System.out.println("(4) Display Game Help");
            System.out.println("(5) Exit Game");
            System.out.println("Choose an option: ");

            try {
                choice = Integer.parseInt(scanner.nextLine());
                if (choice < 1 || choice > 5) {
                    System.err.println("Error : Choose an option between 1 and 5");
                    choice = 0;
                }
            } catch (NumberFormatException e) {
                System.err.println("Error : Choose an option between 1 and 5");
                choice = 0;
            }

            switch (choice) {
                case 1:
                    createNewPlayer(scanner);
                    break;
                case 2:
                    guessNumber(scanner);
                    break;
                case 3:
                    printStatistics();
                    break;
                case 4:
                    printHelp();
                    break;
                case 5:
                    exit = true;
            }
        }
        scanner.close();
    }

    public void printHelp() {
        System.out.println(" ");
    }

    public void printStatistics() {
        try {
            if (player.getName() == null || player.getName().trim().length() < 1) {
                System.out.println("Player has not been set up!");
            } else {
                System.out.println("Player statistics are: ");
                System.out.println("Name: " + player.getName());
                System.out.println("Wins: " + player.getGamesWon());
                System.out.println("Losses: " + player.getGamesLost());
                System.out.println("Amount won so far: " + player.getTotalWinnings());
                System.out.println("Winnings percentage : "
                        + (((player.getGamesWon()) / (player.getGamesWon() + player.getGamesLost())) * 100));
            }
        } catch (ArithmeticException ae) {
            System.out.println("wins and loss both are 0: divide by zero exception");
        }
    }

    public void guessNumber(Scanner scanner) {
        int compGuess = lng.generate();
        int userGuess = 0;
        int numAttempts = 0;
        int cnum = lng.generateConsole();
        do {
            try {
                System.out.println("Guess a number between 1-100: ");
                userGuess = Integer.parseInt(scanner.nextLine());
                if (userGuess < 1 || userGuess > 100) {
                    System.err.println("Error : your Guess must be between 1-100");
                }
            } catch (Exception e) {
                System.err.println("Error : your Guess must be between 1-100");
            }
        } while (userGuess < 1 && userGuess > 100);
        do {
            if (userGuess > compGuess) {
                System.out.println("Your Guess is: " + userGuess + "and the random number: " + compGuess);
                System.out.println("Sorry, you need to go LOWER  :");
            } else if (userGuess < compGuess) {
                System.out.println("Your Guess is: " + userGuess + "and the random number: " + compGuess);
                System.out.println("Sorry, you need to go HIGHER  :");
            }
            numAttempts++;

            if (userGuess == compGuess) {
                System.out.println("Lucky Number was : " + compGuess + "your  guess was : " + userGuess);
                System.out.println("Congratulations you won " + 10 + "$");
                player.setGamesWon(1);
                player.setTotalWinnings(10);
            }

            if (userGuess != compGuess && (userGuess <= (compGuess + 5)) && (userGuess >= (compGuess - 5))) {
                System.out.println("Lucky Number was : " + compGuess + "your FINAL guess was : " + userGuess);
                System.out.println("Congratulations you won " + cnum + "$");
                player.setTotalWinnings(5);
            } else if (userGuess != compGuess) {
                System.out.println("Lucky Number was : " + compGuess + "your  guess was : " + userGuess);
                System.out.println("Sorry better Luck Next time");
                player.setGamesLost(1);
                player.setTotalWinnings(-1);
            }
        } while (userGuess != compGuess && numAttempts < 3);
    }

    public void createNewPlayer(Scanner scanner) {
        String name = null;
        do {
            try {
                System.out.println("Enter the name of the player: ");
                name = scanner.nextLine();
                if (name.isEmpty()) {
                    System.err.println("Name cannot be empty");
                }
            } catch (Exception e) {}
        } while (name.isEmpty());
        this.player = new Player(name);
    }

    public static void main() {
        Game game = new Game();
        game.eventLoop();
    }

}

Answer 1

do {
        try {
            System.out.println("Guess a number between 1-100: ");
            userGuess = Integer.parseInt(scanner.nextLine());
            if (userGuess < 1 || userGuess > 100) {
                System.err.println("Error : your Guess must be between 1-100");
            }
        } catch (Exception e) {
            System.err.println("Error : your Guess must be between 1-100");
        } 
    } while(userGuess < 1 && userGuess > 100);//incorrect

//correct condition -> while(userGuess < 1 || userGuess > 100); 

a number cannot be less than 1 and greater than 100 at the same time.

Edit 1 : In your 2nd loop the following two condition

1) if (userGuess != compGuess && (userGuess <= (compGuess + 5))
            && (userGuess >= (compGuess - 5))) 

2)else if (userGuess != compGuess)

should only be evaluated if the number of guesses by player exceeds the number of attempts, therefore the two if conditions should be written outside the loop.

Also you need the first while loop to keep the user input valid between 1-100, And your second while loop will be inside it.

The final code will look something like this.

    do {

        do {
            try {
                System.out.println("Guess a number between 1-100: ");
                userGuess = Integer.parseInt(sc.nextLine());
                if (userGuess < 1 || userGuess > 100) {
                    System.err
                            .println("Error : your Guess must be between 1-100");
                }
            } catch (Exception e) {
                System.err
                        .println("Error : your Guess must be between 1-100");
            }
        } while (userGuess < 1 || userGuess > 100);

        System.out.println(" " + userGuess);

        if (userGuess > compGuess) {
            System.out.println("Your Guess is: " + userGuess
                    + "and the random number: " + compGuess);
            System.out.println("Sorry, you need to go LOWER  :");

        }
        if (userGuess < compGuess) {
            System.out.println("Your Guess is: " + userGuess
                    + "and the random number: " + compGuess);
            System.out.println("Sorry, you need to go HIGHER  :");
            System.out.println("if 1");
        }
        numAttempts++;

        if (userGuess == compGuess) {
            System.out.println("Lucky Number was : " + compGuess
                    + "your  guess was : " + userGuess);
            System.out.println("Congratulations you won " + 10 + "$");
            // player.setGamesWon(1);
            // player.setTotalWinnings(10);

        }

    } while (userGuess != compGuess & numAttempts < 3);

    if (userGuess != compGuess && (userGuess <= (compGuess + 5))
            || (userGuess >= (compGuess - 5))) {
        System.out.println("Lucky Number was : " + compGuess
                + " your FINAL guess was : " + userGuess);
        // System.out.println("Congratulations you won " + cnum + "$");
        // player.setTotalWinnings(5);

    } else if (userGuess != compGuess) {
        System.out.println("Lucky Number was : " + compGuess
                + "your  guess was : " + userGuess);
        System.out.println("Sorry better Luck Next time");
        // player.setGamesLost(1);
        // player.setTotalWinnings(-1);

    }

}

Answer 2

尝试将第一个do-while放在第二个do-while的顶部。

Answer 3

while(userGuess < 1 && userGuess > 100);
        do{

This contains the error. The loop should run while the userGuess is between 1 and 100, you have excluded it.

It should be

while(userGuess >= 1 && userGuess <= 100);
        do{

Answer 4

AND condition needs to be changed to an OR condition. Because you want to loop only when the user inputs something lower than 1 or higher than 100.

while(userGuess < 1 && userGuess > 100);  ===> while(userGuess < 1 || userGuess > 100);

Again, another AND needs to be changed to OR .

// Issue with logic
if (userGuess != compGuess && (userGuess <= (compGuess + 5)) &&
               (userGuess >= (compGuess - 5))) {

// Corrected Code
if (userGuess != compGuess && (userGuess <= (compGuess + 5)) ||
               (userGuess >= (compGuess - 5))) {