java - 为没有字段的类创建构造函数

Question

我正在尝试创建一个抽象类（Shape）和三个子类（Square、Circle、Triangle），每个子类都没有字段和一个 void 方法——“drawShape”——用星号绘制每个形状。然后，我应该在我的 main 方法中创建每个 Shape 子类对象的数组并循环调用它们的 drawShape 方法。不幸的是，我不断收到错误消息：File: C:\Users\Robert\Demo.java [line: 13] Error: Syntax error on token(s), misplaced construct(s)

我的问题是如何创建这些 Shape 对象，以及如何实现循环以在这些对象的数组中调用它们的 drawShape 方法。

public abstract class Shape
{
  public abstract void drawShape();
}

public class Square extends Shape
{
  @Override
  public void drawShape()
  {
    System.out.println("****\n" + "*  *\n*  *\n****");
  }
}

public class Circle extends Shape
{
  @Override
  public void drawShape()
  {
    System.out.println("   " + "*" + "\n  " + "* *" + "\n " + 
                       "*   *" + "\n  " + "* *" + "\n   " + "*");
  }
    }

public class Triangle extends Shape
{
  @Override
  public void drawShape()
  {
    System.out.println("   " + "*" + "   " +
                       "\n  " + "* *" + "  " + 
                       "\n " + "***" + " ");
  }
}

public class Demo
{
  public static void main(String[] args)
  {
    Triangle triangle = new Triangle();
    Circle circle = new Circle();
    Square square = new Square();
    Shape[] shapes = new Shape{triangle, circle, square};
    //How can I properly create this array^
    //How can I loop through the array to call each objects drawShape method

  }
}

标签： javaarraysinheritanceconstructor

Answer 1

像这样：

Shape[] shapes = new Shape[] {triangle, circle, square};