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A virtual base class doubt

(2 posts)

1. 

   geek4u
   guest
   Posted 1 year ago #
   
   

   Following program prints 8 on Dev CPP compiler.

   #include<iostream>
   using namespace std;
   
   class base {  int i; };
   
   class d1: public  base { };
   
   class d2: public  base { };
   
   class derived: public d1, public d2 { };
   
   int main(void)
   {
     cout<<sizeof(derived);
     getchar();
     return 0;
   }
   

   But, following program instead of printing 4, is printing 12, why??

   #include<iostream>
   using namespace std;
   
   class base {  int i; };
   
   class d1: public virtual base { };
   
   class d2: public virtual base { };
   
   class derived: public d1, public d2 { };
   
   int main(void)
   {
     cout<<sizeof(derived);
     getchar();
     return 0;
   }
   

2. 

   Angshuman jana
   guest
   Posted 1 year ago #
   
   

   base is declared virtual.....when ever inheriting virtual class it adds 4bytes for virtual property..........once it has inherited virtual property any no of inheritence is same like 1 time inherit

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