Question

任何人都可以帮助我。我想通过方法isFaster(Car otherCar)来比较两辆车是否更快。有人可以帮助我理解Car对象如何与作为otherCar方法的参数的isFaster对象进行比较。我怎样才能创建该方法的主体。

public class Car {
  private String make ="";
  private int year = 0;
  private int maxSpeed = 0;

  public Car(String make,int year,int maxSpeed){
    this.make = make;
    this.maxSpeed = maxSpeed;
    this.year = year;
  }

  public void setSpeed(int maxSpeed){
    this.maxSpeed = maxSpeed;
  }

  public void setMake(String make){
    this.make = make;
  }

  public void setYear(int year){
    this.year = year;
  }

  public int getMaxSpeed(){
    return maxSpeed;
  }

  public int getYear(){
    return year;
  }

  public String getMake(){
    return make;
  }

  public String toString(double param){
    String temp = String.valueOf(param);
    return temp;
  }

  public String toString(int param){
    String temp = String.valueOf(param);
    return temp;
  }

  public String toString(char param){
    String temp = String.valueOf(param);
    return temp;
  }
}

Answer 1

在Car对象中，必须有一些属性，比如说

class Car{

    int gear;
    double speed;
}

当您需要进行比较时，您需要根据决定属性来决定比较。

如果它的速度那么

// isFaster will only return true if the calling car object is faster 
// than the otherCar

// for your class this should work

isFaster(Car otherCar){       
    return this.getMaxSpeed() - otherCar.getMaxSpeed()  ;
}

// If you use double for speed, and you need precision
// you can set some tolerance value for comparisons.

isFaster(Car otherCar){       
    return (this.getMaxSpeed() - otherCar.getMaxSpeed() ) < TOLERANCE ;
}

希望这有帮助。

Answer 2

假设Car类有double getMaxSpeed ()等方法，您可以按如下方式实现isFaster (Car otherCar)：

boolean isFaster (Car otherCar) {
    return this.getMaxSpeed() > otherCar.getMaxSpeed ();
}

Answer 3

你必须根据速度覆盖 .equals（）方法，然后才能有意义地比较你的对象。否则默认 .equals（）使用 == 来比较对象，在这种情况下，对象只有在相同时才可以相等

Answer 4

创建一个像这样的方法

public boolean isFaster(Car anotherCar){
   return this.maxSpeed > anotherCar.maxSpeed;
}

在客户端代码示例中：

public static void main(String args []){
  Car car1 = new Car();
  car1.setSpeed(200);// should be setMaxSpeed();
  Car car2 = new Car();
  car2.setSpeed(250);

  System.out.println(car1.isFaster(car2));// prints false

}

创建一个返回布尔值的方法，将对象作为参数

4 个答案: