在主程序中动态创建一个三角形对象和一个长方形对象，并赋于父类接口，然后通过多态的方法得到动态产生对象的周长和面积，并显示这个对象的基本信息。-In the main program to dynamically create a triangular object and a rectangular object, and assigns the interface of the parent class, and then the perimeter and area of the dynamically generated objects polymorphic and displays basic information about the object.