Implement object-oriented interface programming in pure C

Create the following file directory:

Shape. h

#include <stdlib.h> Interface struct Class struct SHAPE_H_* (* (*p_shape Shape( _Shape( * /* SHAPE_H_ */

Shape. c

#include = (p_shape) malloc(->edge =->getEdge =->calcArea = _Shape( * (NULL != shape-> -

Triangle. h

#include  TRIANGLE_H_* (* (*p_triangle Triangle( bottom,  _Triangle( * /* TRIANGLE_H_ */

Triangle. c

#include  bottom, = (p_triangle) malloc(->bottom =->height =->super = Shape(->getEdge =->calcArea = _Triangle( * (NULL != triangle->super-> triangle->bottom * triangle->height / 

Rectangle. h

#include  RECTANGLE_H_* (* (*p_rectangle Rectangle( bottom,  _Rectangle( * /* RECTANGLE_H_ */

Rectangle. c

#include  bottom, = (p_rectangle) malloc(->bottom =->height =->super = Shape(->getEdge =->calcArea = _Rectangle( * (NULL != rectangle->super-> rectangle->bottom * rectangle->

Main. c

#include <stdio.h>= Triangle(, , triangle->, triangle->= Rectangle(, , rectangle->, rectangle-> 

The result is as follows: