java - 如何在main中使用方法变量？

Question

对于我的学校，我需要创建一种将 bug 向任意方向移动的方法。我有以下代码:

package Test;

//imports
import java.util.Scanner;
import java.util.Random;

public class test {
    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        ABug[] BugObj = new ABug[4]; //Creating object BugObj of class ABug
        int loop = 1;
        int i = 0;
        do {
            BugObj[i] = new ABug();  //creating instance
            System.out.println("Please enter the name of the bug:");   
            BugObj[i].name = reader.next(); 
            System.out.println("Please enter the species of the bug:");   
            BugObj[i].species = reader.next(); 
            System.out.println("Please enter the horizontal position of the bug:");   
            BugObj[i].horpos = reader.nextInt();
            System.out.println("Please enter the vertical postion of the bug:");   
            BugObj[i].vertpos = reader.nextInt();   

            System.out.println("_______________ Bug " +(+i+1) + " _______________\n" );
            System.out.println("Name: " + BugObj[i].name);           //Printing bug information out
            System.out.println("Species: " + BugObj[i].species);
            System.out.println("Horizontal Position: " + BugObj[i].horpos);
            System.out.println("Vertical Postion: " + BugObj[i].vertpos + "\n\n");
            move();

            i++;
            System.out.println("Would you like to enter another bug? \n 0-No,  1-Yes\n");
            loop = reader.nextInt();
        } while(loop == 1);
    }

    public static void move() {
        Scanner reader = new Scanner(System.in);
        System.out.println("Would you like this bug to move?\n 0-No,  1-Yes\n");
        if (reader.nextInt() == 0) {
            System.exit(0);
        }
        int r = (int) (Math.random() * (2- -2)) + -2;
        System.out.println(r);
    }
}

class ABug {                 //ABug class
    int horpos, vertpos, energy, id;
    char symbol;
    String species, name;
}

基本上我需要做的就是使用错误位置的值和方法中生成的随机数。我对 java 很陌生，不确定如何做到这一点，甚至不确定它是否可能。

Answer 1

由于在 java 中对象是通过引用传递的，因此您只需将 ABug 对象传递给 move 函数并更改 horpos、vertpos 属性即可。所以

move(BugObj[i]);

和

public static void move(ABug bug){
        Scanner reader = new Scanner(System.in);
        System.out.println("Would you like this bug to move?\n 0-No,  1-Yes\n");
        if (reader.nextInt() == 0)
        {
            System.exit(0);
        }

        int r = (int) (Math.random() * (2- -2)) + -2;

        int originalHorpos = bug.horpos

        int originalVertpos = bug.vertpos

        // Now just change the attributes however you see fit. i am just adding r
        bug.horpos = originalHorpos + r;

        bug.vertpos = originalVertpos + r

        /*by the way, we dont need to use variables for the original values. something like this would also work 

           bug.horpos += r; 
           bug.vertpos += r;

 i just want to explain that in java when you pass objects, they are passed by reference and hence you have access to all of its members.

*/
        System.out.println(r);


    }

此外，您不需要在 move 函数中再次声明 Scanner 对象。您也可以将其传递给 move 函数，然后根据需要多次读取。