/**
  * 三角形类，继承Shape，实现面积计算
  */
 public class Triangle extends Shape {
     // 底
     private double base;
     // 高
     private double height;
     /**
      * 无参构造
      */
     public Triangle() {}
     /**
      * 带参构造，初始化底和高
      * @param base 底
      * @param height 高
      */
     public Triangle(double base, double height) {
         this.base = base;
         this.height = height;
     }
     /**
      * 实现父类抽象方法，计算三角形面积：底×高/2
      * @return 三角形的面积
      */
     @Override
     public double getArea() {
         return base * height / 2;
     }
     // Getter和Setter
     public double getBase() {
         return base;
     }
     public void setBase(double base) {
         this.base = base;
     }
     public double getHeight() {
         return height;
     }
     public void setHeight(double height) {
         this.height = height;
     }
 }