C-language implementation of classes in C + +

The second interview question: C language How to implement classes in C + +

#include <stdio.h>
//C languages do not have classes, but you can use a struct as a class
//Unlike classes, structs can only define variables, cannot define functions, and can implement their functions 
//define "classes" by means of function pointers. The member variable and the method 
typedef struct person{
	char name;
	int age;
	void (*eatfunction) (struct person this, int num);
} person; 

define function 
void eatfunction (struct person this, int num) {
	printf ("test\n");
} 

The constructor for the definition "class"
//is different from the object-oriented, the C language "class" constructor cannot be placed in "class", can only be placed outside of "class"
//constructor primarily completes the initialization of the variable, and the assignment person of the function pointer 
* Newperson (person *this) {
	this->name = ' A ';
	This->age =;
	This->eatfunction = eatfunction;
} 

The main function calls 
int main () {person person
	;
	Newperson (&person);
	Person. Eatfunction (person,0);
	return 0;

Note: When testing to save in. c format, the. cpp format runs the error, because this is the keyword in C + +.

Reference Blog: http://dongxicheng.org/cpp/ooc/