Question

为什么我的证券（'S'）与唐纳德（'D'）处于同一位置。

地图应该像这样打印出来

[D----]

[-----]

[--S--]

[--P--]

但是它却像这样显示

[S----]

[-----]

[--P--]

public class Main {

    public static void main(String[] args) {

        Map m = new Map();
        Player p = new Player();
        Donald d = new Donald();
        Security s = new Security();

while(true) {

            m.updateMap(p.row, p.col, p.character);
            m.printMap();
            m.updateMap(p.row, p.col, '-');
            m.updateMap(d.row, d.col, d.character);
            m.updateMap(s.row, s.col, s.character);
            p.move();

        }

    }

}

public class Map {

    char map[][];

    Map() {
        map = new char[5][5];


        for(int i = 0; i<5; i++) {

            for(int j = 0; j<5; j++) {
                map[i][j] = '-';
            }
        }
    }


    void updateMap(int row, int col, char data) {

        map[row][col] = data;
    }


    //prints map on the screen. 
    void printMap() {
        for(int i = 0; i<5; i++) {
            for (int j = 0; j<5; j++) {
                System.out.print(map[i][j] + " ");
            }

            System.out.println();
        }
    }

}

public abstract class Position {

    int row;
    int col;
    char character;
    abstract void move();

}

public class Donald extends Position {

    //Doanld Trump's Position on the Array is [0,0]
    Donald() {
        int row = 0;
        int col = 0;
        character = 'D';
    }

    void move() {

    }

}

因此，正如您在此处看到的那样，我将安全性位置设置为[3,2]，但是由于某种原因，它无法将其识别为[3,2]，并将安全性放置在唐纳德坐在的[0,0]

public class Security extends Position {

    Security() {
        int row = 3;
        int col = 2;
        character = 'S';
    }

    void move() {

    }

}

import java.util.Scanner;

public class Player extends Position{

    //players position starts at [4,2] on the array
    Player() {
        row = 4;
        col = 2;
        character = 'P';
    }

    void move() {

        Scanner scanner = new Scanner(System.in);
        boolean move = false;
        while(!move) {
            System.out.println("up: w | down: s | left: a | right: d | quit: q");

            char userInput = scanner.next().toLowerCase().charAt(0);


            //moving forward
            if(userInput == 'w') {
                if(row>0) {
                    row--;
                    move = true;
                }
            }

            //moving left
            if(userInput == 'a') {
                if(col>0) {
                    col--;
                    move=true;
                }
            }

            //moving right
            if(userInput == 'd') {
                if(col<4) {
                    col++;
                    move=true;
                }
            }

            //moving down
            if(userInput == 's') {
                if(row<8) {
                    row++;
                    move=true;
                }
            }


            if(move == false) {
                System.out.println("You can't move here");
            }
        }



    }

}

Answer 1

类Security从row继承属性col和Position，但是在构造函数中，您正在这样做：

Security() {
    int row = 3;          //you are basically creating a new variable called row
    int col = 2;          //which is NOT the attribute (that is this.row)
    character = 'S';
}

在构造函数之后，Security对象与s.row保持在一起，并且s.col等于0。

你应该做

Security() {
    this.row = 3;          //you can also do        row = 3;
    this.col = 2;          //and the compiler will understand
    this.character = 'S';
}

您在Donald中犯了同样的错误：您告诉Donald处于位置（0,0），然后又告诉Security处于位置（0,0），这就是Security出现但Donald没有出现的原因，他被Security覆盖。

Player处于您设置的第4行和第2列。

玩家在阵列中的位置

1 个答案: