电梯程序

Question

我已经在这个电梯程序上工作了很长一段时间了，并最终完成了它并使它工作起来，我为自己感到骄傲，但我想知道如何优化我的代码，以便我可以为未来学习。通过优化，我的意思是使代码看起来更好，也许通过使用更少的代码行。

import java.awt.geom.*;

public class elevator
{

    static int floor = 0, choice1, person = 0;

    public static void main(String args[])
    {

        floor = ((int) (Math.random() * 10 + 1));

        System.out.println("The elevator is now on floor " +floor);
        System.out.print("Which floor are you at now (0-10) where 0 = basement: ");
        choice1 = Keyboard.readInt();

        if(floor == choice1)
        {
            System.out.println("Enter the elevator");
        }

        else if(floor > choice1)
        {
            ElevatorDown();
        }

        else if(floor < choice1)
        {
            ElevatorUp();
        }

        System.out.println("To which floor would you want to go (0-10) where 0 = basement");
        choice1 = Keyboard.readInt();

        if(floor > choice1)
        {
            ElevatorDown();
        }

        else if(floor < choice1)
        {
            ElevatorUp();
        }

    }

    public static void ElevatorUp()
    {
        System.out.println("The elevator is on it's way up...");

        for (person = choice1; choice1>=floor; floor++)

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }

    public static void ElevatorDown()
    {
        System.out.println("The elevator is on it's way down...");
        for (person = choice1; choice1<=floor; floor--)

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }
}

Answer 1

import java.awt.geom.*;

public class elevator

类名通常是大写的。

{

    static int floor = 0, choice1, person = 0;

喜欢局部变量而不是这样的静力学。人似乎没有被使用。

    public static void main(String args[])
    {

        floor = ((int) (Math.random() * 10 + 1));

你有另外一对你不需要的父母。

        System.out.println("The elevator is now on floor " +floor);
        System.out.print("Which floor are you at now (0-10) where 0 = basement: ");
        choice1 = Keyboard.readInt();

        if(floor == choice1)
        {
            System.out.println("Enter the elevator");
        }

        else if(floor > choice1)
        {
            ElevatorDown();
        }

        else if(floor < choice1)
        {
            ElevatorUp();
        }

而不是将您的选择保留在静态变量中。将其作为参数传递给ElevatorUp()/ElevatorDown()移动函数。

        System.out.println("To which floor would you want to go (0-10) where 0 = basement");
        choice1 = Keyboard.readInt();

        if(floor > choice1)
        {
            ElevatorDown();
        }

        else if(floor < choice1)
        {
            ElevatorUp();
        }

这是以前重复的。编写一个ElevatorMove()函数，该函数决定是调用ElevatorUp还是ElevatorDown。

    }

    public static void ElevatorUp()
    {
        System.out.println("The elevator is on it's way up...");

        for (person = choice1; choice1>=floor; floor++)

在循环中声明循环变量，而不是其他随机位置。person呢？人和它有什么关系？事实上，person=choice1什么也不做。我会把这做个时间循环。

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }

    public static void ElevatorDown()
    {
        System.out.println("The elevator is on it's way down...");
        for (person = choice1; choice1<=floor; floor--)

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }

这两种功能是相似的。它们可以结合在一起。}

我修改了你的代码：

import java.awt.geom.*;

public class elevator
{

    static int floor;

    public static void main(String args[])
    {

        floor = (int) (Math.random() * 10 + 1);

        System.out.println("The elevator is now on floor " +floor);
        System.out.print("Which floor are you at now (0-10) where 0 = basement: ");
        int current_floor = Keyboard.readInt();

        if(floor == current_floor)
        {
            System.out.println("Enter the elevator");
        }
        else
        {
            MoveElevator(current_floor);
        }


        System.out.println("To which floor would you want to go (0-10) where 0 = basement");
        int target_floor = Keyboard.readInt();

        MoveElevator(target_floor);
    }

    public static void MoveElevator(int target_floor)
    {
        int direction;
        if( target_floor > floor )
        {
            System.out.println("The elevator is on it's way up...");
            direction = 1;
        }else{
            System.out.println("The elevator is on it's way down...");
            direction = -1;
        }

        while(target_floor != floor)
        {
            floor += direction;
            System.out.println(floor);
        }

        System.out.println("The elevator has arrived");
    }
}

Answer 2

您应该将main方法从Elevator类中分离出来，这样您的Elevator类才能真正代表电梯！比方说，您可以拥有一个Program类，它将调用您的Elevator类。

其次，您的方法和字段不应该是静态的。通常，当您的类具有状态(例如当前地板)时，您的对象不应该是静态的。这样，您就可以拥有2个(或更多) Elevator实例，并且它们不会碰撞在一起。

电梯不应该从一个随机的楼层开始，想象一下真正的电梯。在第一次使用时，它很有可能从底层开始(至少，我想，我不是电梯专家！)让我们在0楼(地下室)启动这台电梯。

所以现在，我假设你的电梯只有一个人使用，因为一个真正的电梯可能不会来接你，如果它没有朝你想要的方向走。

类名应该是大写的，而命名的方法应该是camelCased，因此：

Elevator而不是elevator

elevatorUp而不是elevatorUp

elevatorDown而不是elevatorDown

而且，Java约定指定您的括号应该是“埃及风格”。这意味着：

//Good
if{
}

//Less good
if
{
}

这是我解释的简历：

public class Elevator {
    private int floor = 0, choice1, person = 0;

    public void callFrom(int floor){
        System.out.println("Elevator is coming");
        goTo(floor);
    }

    public void goTo(int floor){
        if(floor == choice1) {
            System.out.println("Enter the elevator");
        }
        else if(floor > choice1) {
            elevatorDown();
        }

        else if(floor < choice1){
            elevatorUp();
        }
    }

    private void elevatorUp() {
        System.out.println("The elevator is on it's way up...");

        for (person = choice1; choice1>=floor; floor++)

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }

    private void elevatorDown() {
        System.out.println("The elevator is on it's way down...");
        for (person = choice1; choice1<=floor; floor--)

            System.out.println(floor);

        System.out.println("The elevator has arrived");
    }
}

我不确定goTo和callFrom，但我认为把它们分开很重要，因为如果你想让电梯变得更加复杂(处理多个电话等等)你得把他们分开。

Answer 3

在面向对象编程中，您通常会问自己:我使用哪些对象操作，我可以对它们做什么，以及它们的属性是什么？就你而言：

• 有一部电梯，可能有很多电梯，它们都是相似的。
• 电梯的当前楼层总是在目前的位置。
• 电梯运行时，目前的楼层可能会发生变化。
• 一个典型的动作是向上移动。
• 另一个典型的动作是向下移动。
• 当一个人想要使用电梯时，电梯移动到该人所在的楼层。一般说来，电梯会移动到一定的楼层。

下面是基于上述描述的代码：

public class Elevator {

  private int currentFloor;

  public void run() {
    currentFloor = 1 + ((int) (Math.random() * 10));

    System.out.println("The elevator is now on floor " + currentFloor);
    System.out.print("Which floor are you at now (0-10) where 0 = basement: ");
    int personFloor = Keyboard.readInt();
    moveTo(personFloor);
    System.out.println("Enter the elevator");

    System.out.println("To which floor do you want to go (0-10) where 0 = basement");
    int destinationFloor = Keyboard.readInt();
    moveTo(destinationFloor);
    System.out.println("Leave the elevator");
  }

  private void moveTo(int destinationFloor) {
    if (destinationFloor == currentFloor) {
      /* nothing to do */
    } else if (destinationFloor > currentFloor) {
      moveUpTo(destinationFloor);
    } else {
      moveDownTo(destinationFloor);
    }
  }

  private void moveUpTo(int destinationFloor) {
    System.out.println("The elevator is on its way up ...");
    while (currentFloor < destinationFloor) {
      currentFloor++;
      System.out.println(currentFloor);
    }
    System.out.println("The elevator has arrived");
  }

  private void moveDownTo(int destinationFloor) {
    System.out.println("The elevator is on its way down ...");
    while (currentFloor > destinationFloor) {
      currentFloor--;
      System.out.println(currentFloor);
    }
    System.out.println("The elevator has arrived");
  }

  public static void main(String[] args) {
    new Elevator().run();
  }

}

顺便说一下，电梯在路上，而不是在路上。