Question

该Java程序应该要求用户输入最大值，然后生成1到该最大值之间的随机数。然后用户猜测它的值是什么，直到它们正确为止。当用户不正确时，程序会告诉他们它们太高或太低并且增加了猜测次数。如果用户是正确的，程序会显示猜测的总数，并询问用户是否想再次播放。

我一直存在的问题是，有时候，当我输入一个猜测时，程序会跳过来告诉我，我太高，太低或者说不对，只是问我是否想再玩一次。我无法弄清楚为什么会这样，而且似乎是随机发生的。

import java.util.Scanner;

public class GuessNumber 
{


public static void main (String [] args)
{

    Scanner in = new Scanner (System.in); //create scanner object
    int maxNumber = 0; //declare variables
    int userGuess = 0;
    int totalGuesses = 0;
    int secretNumber = 0;
    String replay = "";

    System.out.println("Welcome to the Secret Number Generator!");

    do
    {
        System.out.println("Please input a maximum value for the secret number and press enter."); //prompt user to input a maximum value
        maxNumber = in.nextInt();

        secretNumber = (int) ((Math.random() * maxNumber) + 1); //generate the secret number

        System.out.println("A new secret number has been chosen!"
                + "\nWhat do you think it is? Input your guess and press enter."); //prompt user to input a guess
        userGuess = in.nextInt();

        while (userGuess < secretNumber) //while user's guess is less than the secret number
        {
            System.out.println("Sorry, that is too low! Please try again."); //prompt user to input another guess; increment total number of guesses by 1
            userGuess = in.nextInt();
            totalGuesses ++;
        }

        while (userGuess > secretNumber) //while user's guess is greater than the secret number
        {
            System.out.println("Sorry, that is too high! Please try again."); //prompt user to input another guess; increment total number of guesses by 1
            userGuess = in.nextInt();
            totalGuesses ++;
        }

        if (userGuess == secretNumber) //if user guesses correctly
        {
            System.out.println("Nice job! Your guess, " + secretNumber + " is correct!" //congratulate and display total number of guesses
                    + "\nTotal number of guesses: " + totalGuesses);
        }

        System.out.println("Would you like to play again? Please input \"Yes\" or \"No\" and press enter."); //ask user if they would like to play again
        replay = in.next();

        while (!replay.equalsIgnoreCase("Yes") && !replay.equalsIgnoreCase("No") //in case of invalid input
                && !replay.equalsIgnoreCase("\"Yes\"") && !replay.equalsIgnoreCase("\"No\""))
        {
            System.out.println("Sorry, that is an invalid input. Please input \"Yes\" or \"No\" and press enter.");
            replay = in.next();
        }
    }   
    while(replay.equalsIgnoreCase("Yes") || replay.equalsIgnoreCase("\"Yes\"")); //replay while user says yes

    if (replay.equalsIgnoreCase("No") || replay.equalsIgnoreCase("\"No\"")) //if user says no
    {
        System.out.print("Thanks for playing!");
    }

} //end of main method


} //end of class GuessNumber

Answer 1

不要将while循环用于单个评估条件。用这样的东西（伪代码）替换你的三个内部while循环：

int guess = readInteger()
while guess != number
    if guess < number print "too low"
    if guess > number print "too high"
assert guess == number
print "you guessed correctly; good job!"

然后通过游戏循环运行，以保持游戏的进行。

Answer 2

你有多个while循环没有意义。如果用户输入更大的数字然后输入小数字，它将跳过它。

你可以将它们全部收缩到其中一个

while (userGuess != secretNumber){
   if(userGuess > secretNumber){
     //too high
   } else if(userGuess < secretNumber){
     //too low 
   } else{
     //nice got it
   }

}

//do you want to play again 
...

Answer 3

看起来你遇到了一些循环问题，就像其他人建议的那样，当一个简单的选择结构如“if else”或“select case”工作时，请避免这么多不必要的嵌套循环。应该这样节省你一些大惊小怪。

为了让您的应用程序更可预测地运行，我建议将“游戏”逻辑放入方法中。这是一个运行的例子。希望它可以帮到你一些！

import java.util.Scanner;

public class GuessNumber {

public static void main(String[] args) {

    Scanner in = new Scanner(System.in);
    String replay = "";

    do {
    runGame(); //run method to guess number
    System.out.println("Play again? Enter Yes or No");
    replay = in.nextLine().toLowerCase();
    }
    while(!replay.equals("no"));
}

private static void runGame() {
    Scanner in = new Scanner(System.in); //create scanner object
    int maxNumber = 0; //declare variables
    int userGuess = 0;
    int totalGuesses = 0;
    int secretNumber = 0;


    System.out.println("Welcome to the Secret Number Generator!");
    System.out.println("Please input a maximum value for the secret number and press enter."); //prompt user to input a maximum value
    maxNumber = in.nextInt();

    secretNumber = (int) ((Math.random() * maxNumber) + 1); //generate the secret number

    System.out.println("A new secret number has been chosen!" + "\nWhat do you think it is? Input your guess and press enter."); //prompt user to input a guess
    userGuess = in.nextInt();

    while (userGuess != secretNumber) {
        if (userGuess < secretNumber) {
            System.out.println("Sorry, that is too low! Please try again."); //prompt user to input another guess; increment total number of guesses by 1
        } else if (userGuess > secretNumber) {
            System.out.println("Sorry, that is too High! Please try again."); //prompt user to input another guess; increment total number of guesses by 1
        }
        else {
            System.out.println("Sorry, but that's not right. Try again...");
        }

        totalGuesses++;
        userGuess = in.nextInt();
    }
    System.out.println("You guessed it! After " + totalGuesses + "   tries.");
    }
}

初学Java秘密数字猜测程序

3 个答案: