先创建一个Point类，然后定义Trianglele类。在Trianglele类中定义三个Point的实体来表示一个三角形的三个点，再定义一个方法setTri对这三个点进行初始化，然后定义两个方法求三角形的周长、面积。在main()中创建一个对象，求给定三点的三角形的周长、面积。-First create a Point class, and then define Trianglele class. Defined in the Trianglele Three Point class of entities to represent a triangle of three points, and then define a method to initialize setTri these three points, then define two methods find the perimeter of the triangle area. In the main () to create an object, find the point of the triangle given perimeter, area.