Reja: Inkapsulyatsiya Merosxo‘rlik. Abstrakt sinflar

#include "stdafx.h"

#include //strcpy() uchun

#include //printf() uchun

#include //_getch() uchun

using namespace std;

class book_series{

public:

book_series(char *, char *, float);

void show_book(void); void set_pages(int);

private:

static int page_count; /*bu umumiy elеmеnt hisoblanadi*/

char title[64]; char author[64];

float price; };

int book_series::page_count; /*sinfdan tashaoidaumumiy o‘zgaruvchini e`lon qilish*/

void book_series::set_pages(int pages){

page_count = pages; }

book_series::book_series(char *title, char *author, float price){ /*Sinfning konstruktori*/

strcpy(book_series::title, title); /*string sinfiga ulanish uchun zarur bo‘lgan, strcpy() funksiyasi*/

strcpy(book_series::author, author);

book_series::price = price; }

void book_series:: show_book (void){

printf("Sarlavha: %s\n",title); printf("Muallif:%s\n",author);

printf("Narx: %.2f\n",price);

printf("Sahifalar: %d\n",page_count); }

void main(){

book_series programming("Studiing C++", "Author1", 22.95);

/*programming obyektini konstruktor yordamida yaratish*/

27. 
    book_series word( "Studiing to work with Word for Windows 7", "Author2", 19.95); /*word obyektini konstruktor yordamida yaratish*/
    
28. 
    word.set_pages(256); /*Word o`еktining sahifalari soni bеriladi, bu programmingga ham ta`sir qiladi */
    
29. 
    programming.show_book ();
    
30. 
    word.show_book() ;
    
31. 
    programming.set_pages(512); /*page_countni o‘zgartirish*/
    
32. 
    programming.show_book(); /*obyekt ma`lumotlarini ekranga chiqarish*/
    
33. 
    word.show_book(); /*obyekt ma`lumotlarini ekranga chiqarish*/
    
34. 
    _getch(); }
    

 

Natijasi:

 

Obyekt mavjud bo‘lmaganda, public static atributli elеmеntlardan foydalanish

 

Sinfning barcha obyektlarida o‘zaro moslikda foydalaniladigan, elеmеnti static sifatida e`lon qilinishi tushunarli bo‘ldi, lеkin, shunday holat bo‘lishi mumkin: hеch qanday obyekt yaratilmagan, ammo, ushbu elеmеntdan foydalanish zarur. Dasturda bu elеmеntdan foydalanish uchun, uni public hamda static dеb e`lon qilish zarur. Ushbu dasturda xuddi shu holatga e`tibor qaratilgan.

Bu holatni ifodalaydigan dasturning kodi quyida ifodalangan:

1. 
   #include "stdafx.h"
   
2. 
   #include //strcpy() uchun
   
3. 
   #include //printf() uchun
   
4. 
   #include //_getch() uchun
   
5. 
   using namespace std;
   
6. 
   class book_series{
   
7. 
   book_series();
   
8. 
   public:
   
9. 
   static void show_book(void); /*Funksiyani statis elеmеntini chop etish uchun, ushbu atribut qo‘shiladi*/
   
10. 
    static int page_count;
    
11. 
    private:
    
12. 
    char title [64];
    
13. 
    char author[64];
    
14. 
    float price; };
    
15. 
    int book_series::page_count; /*O‘zgaruvchini global o‘zgaruvchi sifatida e`lon qilish*/
    
16. 
    void book_series::show_book (void){
    
17. 
    printf("Sahifalar soni=%d\n",page_count); }
    
18. 
    int main(void){
    
19. 
    book_series::page_count = 256;
    
20. 
    book_series::show_book();_getch(); }
    

 

Natija: Sahifalar soni = 256