java - Deitel Java 练习 6.30

Question

我错过了将实现放在驱动程序类中的要点，而不是让驱动程序类仅调用其他类中的方法。我不确定如何将实现移到主类之外。欢迎提出建议!

/*
*Deitel Chapter 6 Exercise 6.30
*/
package guess;


import java.util.Scanner;

/**
*Driver class for number guessing game
*/
public class GuessDriver {

/**
 *
 * @param args
 */
public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    /*
     *instantiate guess class
     */       
    Guess Guess = new Guess();


    /*
    *loops program until user guesses correct number
    */        
    while (Guess.getGuess() != Guess.secretNumber){  
    /*
    *takes input from user
    n*/       
    System.out.println("Enter a number from 1 to 1000: ");
    int setGuess = input.nextInt();
    Guess.setGuess(setGuess);

   /* 
    *nested if-else statements compares guess against secret number
    */       
    if(Guess.secretNumber < Guess.guess){
        System.out.println("too high");
    } else if (Guess.secretNumber > Guess.guess){
        System.out.println("too low");
     } else {
        System.out.println("Congratulations, you win!");
     } 
    }
}
}

/*
*Deitel Chapter 6 Exercise 6.30
*/
package guess;
import java.util.Random;

/**
* Takes in and stores an integer, sets value for random number
*/
public class Guess {


/**
 *instance variable
 */
public int guess;

/**
 *instance variable
 */
public int secretNumber = (int) (Math.random() * 999 + 1);

/**
 *return secret number
 * @return
 */
public int getSecretNumber() {
    return secretNumber;
}

/**
 *return guess
 * @return
 */
public int getGuess() {
    return guess;
}


/**
 *set guess
 * @param guess
 */
public void setGuess(int guess) {
    this.guess = guess;
}

}

Answer 1

嗯，首先。我建议将 Guess 类的所有变量设为私有(private)。 (请注意，您有一个 getSecretNumber() 方法，该方法已经为您提供了 SecretNumber 变量的值。

其次，您可以在 Guess 类中创建一个公共(public)方法，例如 checkGuessing(int Guess)。此方法将接受用户输入，并在控制台上写下答案(“太高”、“太低”等)。另一种选择可能是将相同的功能添加到 setGuess 方法中。

最后，为了方便以后的调试，您应该用大写字母命名类，用驼峰式字母命名变量(甚至类的实例)，并尝试以不同于类名的方式命名该类的变量。

所以最终的代码可能是这样的:在 GuessDriver 类中:

package guessdriver;
import java.util.Scanner;

/**
*Driver class for number guessing game
*/
public class GuessDriver {

/**
 *
 * @param args
 */
public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    /*
     *instantiate guess class
     */       
    Guess guess = new Guess();


    /*
    *loops program until user guesses correct number
    */        
    while (guess.checkGuessing()==false){  
    /*
    *takes input from user
    n*/       
    System.out.println("Enter a number from 1 to 1000: ");
    int setGuess = input.nextInt();
    guess.setGuess(setGuess);



    }
}
}

在 Guess 类中:

package guessdriver;

public class Guess {


/**
 *instance variable
 */
private int guessing;

/**
 *instance variable
 */
private int secretNumber = (int) (Math.random() * 999 + 1);

/**
 *return secret number
 * @return
 */
public int getSecretNumber() {
    return secretNumber;
}

/**
 *return guess
 * @return
 */
public int getGuess() {
    return guessing;
}


/**
 *set guess
 * @param guess
 */
public void setGuess(int guessing) {
    this.guessing = guessing;
}
public boolean checkGuessing(){
    if(secretNumber < guessing){
        System.out.println("too high");
        return false;
    } else if (secretNumber > guessing){
        System.out.println("too low");
        return false;
     } else {
        System.out.println("Congratulations, you win!");
        return true;
     }
}
}