2-1什么是面向对象

object=entity

object may be

        visible

        invisible

Object is variable in programming language.

data:the properties or status

Operation:the functions

From the problem space to the solution one. ​​​​​​​

C doesn't support relationship btw data and functions. 

typedef struct point3d{
    float x;
    float y;
    float z;
}Point3d;

void Point3d_print(const Point3d* pd);

Point3d a;
a.x=1;a.y=2;a.z=3;
Point3d_print(&a);

C++ 

class Point3d{
public:
    Point3d(float x,float float z);
    print(); 
private:
    float x;
    float y;
    float z;
};

Point3d a(1,2,3);
a.print();

A way to organiaze

        Designs

        Implementations

Object, not control or data flow, are the primary focus of the design and implementation. 

To focus on things, not operations.