[C] How to Use C to practice OOP

Because of work needs, it is now necessary to use C to develop the program of the ingress-type system.

To enhance the skill, let's take a look at how to use C to practice oop.

This example is based on xcode3.2.3 + gcc4.2 ......

This is a little different from the examples found by Google .....

Http://stackoverflow.com/questions/351733/can-you-write-object-oriented-code-in-c

 

# Include <stdio. h> <br/> # include <stdlib. h> <br/> typedef void (* pai_fun) (struct animal * a_this); <br/> typedef struct animal * (* dtor_fun) (struct animal * a_this ); <br/> typedef struct _ animal_vtable {<br/> pai_fun walk; <br/> dtor_fun dtor; <br/>} animal_vtable; <br/> typedef struct _ animal {<br/> animal_vtable vtable; </P> <p> char * Name; <br/>} animal; <br/> typedef struct _ dog {<br/> animal_vtable vtable; </P> <p> char * Name; // mirror member variables for easy access <br/> char * type; <br/>}dog; <br/> void animal_walk (animal * a_this) {<br/> printf ("Animal (% s) walking/N", a_this-> name ); <br/>}< br/> struct animal * animal_dtor (struct animal * a_this) {<br/> printf ("Animal: dtor/N "); <br/> return a_this; <br/>}< br/> animal * animal_alloc () {<br/> return (animal *) malloc (sizeof (animal )); <br/>}< br/> animal * animal_new (animal * a_animal) {<br/> a_animal-> vtable. walk = animal_walk; <br/> a_animal-> vtable. dtor = animal_dtor; <br/> a_animal-> name = "anonymous"; <br/> return a_animal; <br/>}< br/> void animal_free (animal * a_this) {<br/> a_this-> vtable. dtor (a_this); </P> <p> free (a_this); <br/>}< br/> void dog_walk (dog * a_this) {<br/> printf ("dog walking % s (% s)/n", a_this-> type, a_this-> name ); <br/>}< br/> dog * dog_dtor (dog * a_this) {<br/> // explicit call to parent destructor <br/> animal_dtor (animal *) a_this); </P> <p> printf ("Dog: dtor/N"); </P> <p> return a_this; <br/>}< br/> dog * dog_alloc () {<br/> return (dog *) malloc (sizeof (DOG )); <br/>}< br/> dog * dog_new (dog * a_dog) {<br/> // explict call to parent constructor <br/> animal_new (animal *) a_dog); </P> <p> a_dog-> type = "dog type"; <br/> a_dog-> vtable. walk = (pai_fun) dog_walk; <br/> a_dog-> vtable. dtor = (dtor_fun) dog_dtor; </P> <p> return a_dog; <br/>}</P> <p> int main (INT argc, const char * argv []) {<br/>/* <br/> base class: <br/> animal * a_animal = animal_new (animal_alloc ()); <br/> */<br/> animal * a_animal = (animal *) dog_new (dog_alloc (); </P> <p> a_animal-> vtable. walk (a_animal); </P> <p> animal_free (a_animal); </P> <p> return 0; <br/>}< br/>