在方法之外声明整数？答案

【问题标题】：Declaring Integer Outside of Method?在方法之外声明整数？
【发布时间】：2016-03-10 04:23:30
【问题描述】：

    import java.util.Scanner;
public class InputTest {
static void monster() {
    System.out.println("You ran into a monster!");
    System.out.println("He did 10 damage!");
    health -= 10;
    System.out.println("You have " + health + " health left!");
}
static void potion() {
    System.out.println("You ran into a potion!");
    System.out.println("It healed 10 damage!");
    health += 10;
    System.out.println("You have " + health + " health left!");
}
static void bag() {
    System.out.println("You ran into a bag!");
    System.out.println("It did... Nothing!");
}
static void random() {
    double random = Math.random();
    if(random >= 0 && random <= 0.33) {
        monster();
    } else if(random >= 0.24 && random <= 0.66) {
        potion();
    } else {
        bag();
    }
}
static void turn() {
    System.out.println("Do you want to go left or right?");
    Scanner turn = new Scanner(System.in);
    String leftOrRight = turn.nextLine();
    if(leftOrRight.equals("Right")) {
        System.out.println("You turned right and...");
        random();
    } else if(leftOrRight.equals("Left")){
        System.out.println("You turned left and...");
        random();
    } else {
        System.out.println("You entered an invalid answer...");
        System.exit(0);
    }
}
public static void main(String[] args) {
    int health = 50;
    for(int i = 0; i < 10; i++) {
        turn();
    }
    System.out.println("You won!");
    }
}

这是无效的代码。怪物（）；和健康（）；方法是我遇到麻烦的方法。它输出我没有声明“健康”。我明白它为什么这么说，有什么办法可以解决这个问题。它只是不允许我在方法中使用健康整数。如您所见，它应该取健康并减去 10。

【问题讨论】：

将health 设为全局变量。所以在你的怪物方法之上，做public int health = 50;。您可以让方法使用 main 中定义的健康状况。然后为health 创建一个getter/setter
@Ascalonian No. 将health 设为静态类参数。 static int health = 50;
@MikeCAT - 为什么要让它成为静态的？
@Ascalonian 因为它是从静态函数中使用而不创建实例。
嗨，德里克，欢迎来到 SO。请尝试在将来发布minimal reproducible example。这让其他人更容易回答您的问题。

标签： java variables integer declaration

【解决方案1】：

试试下面的代码：

import java.util.Scanner;

public class Test {
    private static int health = 50;

    public static void main(String[] args) {

        for (int i = 0; i < 10; i++) {
            turn();
        }
        System.out.println("You won!");
    }

    static void monster() {
        System.out.println("You ran into a monster!");
        System.out.println("He did 10 damage!");
        health -= 10;
        System.out.println("You have " + health + " health left!");
    }

    static void potion() {
        System.out.println("You ran into a potion!");
        System.out.println("It healed 10 damage!");
        health += 10;
        System.out.println("You have " + health + " health left!");
    }

    static void bag() {
        System.out.println("You ran into a bag!");
        System.out.println("It did... Nothing!");
    }

    static void random() {
        double random = Math.random();
        if (random >= 0 && random <= 0.33) {
            monster();
        } else if (random >= 0.24 && random <= 0.66) {
            potion();
        } else {
            bag();
        }
    }

    static void turn() {
        System.out.println("Do you want to go left or right?");
        Scanner turn = new Scanner(System.in);
        String leftOrRight = turn.nextLine();
        // turn.close();
        if (leftOrRight.equals("Right")) {
            System.out.println("You turned right and...");
            random();
        } else if (leftOrRight.equals("Left")) {
            System.out.println("You turned left and...");
            random();
        } else {
            System.out.println("You entered an invalid answer...");
            System.exit(0);
        }
    }
}

【讨论】：

【解决方案2】：

见下方修改后的代码。

import java.util.Scanner;

public class InputTest {
    private static int health = 50;
    static void monster() {
        System.out.println("You ran into a monster!");
        System.out.println("He did 10 damage!");
        health -= 10;
        System.out.println("You have " + health + " health left!");
    }

    static void potion() {
        System.out.println("You ran into a potion!");
        System.out.println("It healed 10 damage!");
        health += 10;
        System.out.println("You have " + health + " health left!");
    }

    static void bag() {
        System.out.println("You ran into a bag!");
        System.out.println("It did... Nothing!");
    }

    static void random() {
        double random = Math.random();
        if (random >= 0 && random <= 0.33) {
            monster();
        } else if (random >= 0.24 && random <= 0.66) {
            potion();
        } else {
            bag();
        }
    }

    static void turn() {
        System.out.println("Do you want to go left or right?");
        Scanner turn = new Scanner(System.in);
        String leftOrRight = turn.nextLine();
        if (leftOrRight.equals("Right")) {
            System.out.println("You turned right and...");
            random();
        } else if (leftOrRight.equals("Left")) {
            System.out.println("You turned left and...");
            random();
        } else {
            System.out.println("You entered an invalid answer...");
            System.exit(0);
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            turn();
        }
        System.out.println("You won!");
    }
}

问候

【讨论】：

【解决方案3】：

使健康成为类级别的静态变量。

import java.util.Scanner;
public class InputTest {
     private static int health = 50;

     /*rest of the methods as they are*/

}

【讨论】：

static variable - 就这样吧
非常感谢大家，它现在可以工作了，只是做了一些调整。 (:
@ScaryWombat 为什么我们这里需要静态？？
因为从静态方法调用它。