Question

我只是在学习阶段＆amp;我在这里使用一些多态技术。这是代码：

package com.company;
class Car{
    private String name;
    private int cylinder;
    private boolean engine;
    private int wheels;

    public Car(String name, int cylinder) {
        this.name = name;
        this.cylinder = cylinder;
        this.engine = true;
        this.wheels = 4;
    }

    public String startEngine(int fuel){
        if(fuel>0){
            return "Start button pressed";
        } else{
            return "First fill some fuel";
        }
    }

    public String accelerate(int speed){
        return "Car is accelerated with speed " + speed;
    }

    public String brake(int speed){
        return "Brake is presses. Now speed is " + speed;
    }

    public String getName() {
        return name;
    }

    public int getCylinder() {
        return cylinder;
    }
}

class Fortuner extends Car{
    public Fortuner() {
        super("Fortuner", 4);
    }

    @Override
    public String accelerate(int speed) {
        return "Fortuner is accelerated with speed " +speed;
    }

    @Override
    public String brake(int speed) {
        return "Now your Fortuner is moving with " + speed + " kph";
    }
}

class Hondacity extends Car{
    public Hondacity() {
        super("Hinda City", 6);
    }

    @Override
    public String accelerate(int speed) {
        return "Honda City is accelerated with speed " +speed;
    }

    @Override
    public String brake(int speed) {
        return "Now your Honda City is moving with " + speed + " kph";
    }
}

class Omni extends Car{
    public Omni() {
        super("Omni", 1);
    }

    @Override
    public String accelerate(int speed) {
        return "Omni is accelerated with speed " +speed;
    }

    @Override
    public String brake(int speed) {
        return "Now your Omni is moving with " + speed + " kph";
    }
}

public class Main {

    public static void main(String[] args) {
        for(int j=0; j<3; j++){
            Car car = speedup();
            System.out.println(car.accelerate(50));
        }

    }

    public static Car speedup() {
        for(int i=0; i<3; i++){
            switch(i){
                case 0: return new Fortuner();
                case 1: return new Hondacity();
                case 2: return new Omni();
            }
        }
        return null;
    }

}

当我运行它时，它会提供如下输出：

Fortuner以50的速度加速Fortuner加速速度50 Fortuner速度加快50

但我想提供类似这样的输出

Fortuner以50的速度加速速度50 Omni以速度加速50

我知道每次方法运行时都会发生这种情况。我该如何解决？请告诉我糟糕的算法，因为我只是一个学习者。

Answer 1

你的方法O(m+n)总是返回一个Fortuner，因为它永远不会得到任何进一步的结果。 IntersectWith命令始终退出循环。所以，如果你想获得所有课程，你必须这样做：

speedup()

Answer 2

在你的方法speedup（）中，每次j的值都是0.所以它总是返回Fortuner。我已经删除了这个方法来解决它。

public int a;
public string b;

如何在调用方法时增加变量

2 个答案: