java - 在 0,0 坐标处启动 Random Walker java 程序时遇到问题

Question

我正在尝试构建一个程序，该程序采用整数并模拟随机游走的运动，直到随机游走者距起点位于曼哈顿距离 r 处。关键要求之一是在 0,0 坐标处启动程序，但我无法

public class RandomWalker {

    public static void main(String args[]) {

        int r = Integer.parseInt(args[0]);

        int x = 0;
        int y = 0;
        int step = 0;
        double R;
        while(Math.abs(x) < r && Math.abs(y) < r) {
            step++;
            R = Math.random();
            if(R <= 0.25) x++;
            else if (R <= 0.50) x--;
            else if (R <= 0.75) y++;
            else if (R <= 1.00) y--;

            System.out.println("(" + x + ", " + y + ")" );
        }
        System.out.println("steps = " + step);
    }
}

Answer 1

我怀疑你只需要在步进之前打印坐标即可。见下文。我还尝试将 walker 值封装在类中而不是 main 方法中。

public class RandomWalker {
    private final Random random;
    private int steps = 0;
    private int x = 0;
    private int y = 0;

    public RandomWalker(Random random) {
        this.random = random;
    }

    public String toString() {
        return steps + ": (" + x + "," + y + ")";
    }

    public void step() {
        steps++;
        switch (random.nextInt(4)) {
            case 0: x++; break;
            case 1: x--; break;
            case 2: y++; break;
            case 3: y--; break;
        }
    }

    public int distance() {
        return Math.abs(x) + Math.abs(y);
    }

    public static void main(String args[]) {
        int r = Integer.parseInt(args[0]);
        RandomWalker walker = new RandomWalker(new Random());
        while (walker.distance() < r) {
            System.out.println(walker);
            walker.step();
        }
        System.out.println("steps = " + walker.steps);
    }
}