小编Sam*_*Sam的帖子

我正在学习使用课程,我的部分任务是制作这个Car课程.我在第6行遇到错误,我尝试打印类中方法的结果.我认为这意味着我正在尝试打印一些不存在的东西,我怀疑这是里程方法.我尝试将其更改为返回里程,但这也无效.有任何想法吗？

public class TestCar {
  public static final void main(String args[]) {

    Car c = new Car ();
    c.moveForward(4);
    System.out.println ("The car went" + c.mileage() + "miles."); // <-- L6
  }
}

class Car {
  public int miles = 2000;
  public void moveForward(int mf) {
    if (miles != 2000) {
        miles += mf;
    }
  }

  public void mileage() {
    System.out.print(miles);
  }
}

我正在尝试编写一个利用java的Abstract类特性的程序.第63行我得到了一个"非法的表达式开始"错误,它声明了公共类AbstractCar.任何人都可以解释为什么我收到此错误以及如何纠正它.先感谢您

public class AbstractCar {
  public static final void main(String args[]) {

    abstract class Vehicle {
      //subclasses will inherit an attribute
      int maxSpeed;
      //subclasses must implement this method 
      //(otherwise they have to be declared as abstract classes)
      abstract void showMaxSpeed();
      //subclass will have this method (through inheritance) as is (default implementation)
      //or they may implement their own implementation (override a method)
      int getWheelsNumber() {
        return 4;
      }
    }

    /**Car IS-A Vehicle*/
    class Car extends Vehicle {
      public Car() {
        maxSpeed …