Class simulations and polymorphism, inheritance

In object-oriented languages, the concept of classes arises. This is an evolution of programming ideas. Class: A collection of specific operations on specific data. So the class contains two categories: Data and operations. The suct in C language is just a collection of data. (liyuming1978@163.com)

1. Example: Let's look at a small example

#ifndef c_class #define C_class suct #endif c_class A {c_class a *a_this;
       void (*foo) (C_class A *a_this);
       int A;
int b;
 
};  C_class b{//b inherited a c_class B *b_this;              Order is important void (*foo) (C_class B *bthis);
       virtual function int A;
 
       int b;
int C; 
};
 
void B_f2 (C_class B *bthis) {printf ("It is b_fun\n");} void A_foo (C_class A *athis) {printf ("It is a.a=%d\n", athis->a);//or Here//exit (1);//printf ("pure virtual does not allow execution \
 
n ");//or here} void B_foo (C_class B *bthis) {printf (" It is b.c=%d\n ", bthis->c);}
       void A_creat (Suct * p) {p->foo=a_foo;
       p->a=1; 
       p->b=2;
p->a_this=p;
       } void B_creat (Suct b* p) {p->foo=b_foo;
       p->a=11;      
       p->b=12;
       p->c=13;
p->b_this=p;
       int main (int argc, char* argv[]) {c_class A *ma,a;
 
       C_class B *mb,b; A_creat (&a);//instantiated B_creat (&B);
       mb=&b;
 
       ma=&a; Ma= (C_class A *) mb;//introduces polymorphic pointer printf ("%d\n", ma->a);/Unfortunately, the function variable has no private Ma->foo (MA);//polymorphic A.foo (&A
MP;A);//Not polymorphic B_F2 (&b)//member function, because the efficiency problem does not use the function pointer return 0;
 }

Output results:

11
It is b.c=13
It is A.a=1
It is B_fun