virtual inheritance in c++ order of inheritance

Question

#include <iostream>
using namespace std;

class BaseClass_1 {
  public:
    BaseClass_1()
    {
      cout << "you are in  baseclass 1" << endl;
    }
};

class BaseClass_2 {
  public:
    BaseClass_2()
    {
      cout << "you are in baseclass 2" << endl;
    }
};

class Derived_class: public  BaseClass_1, public  BaseClass_2 {
    
    public:
    Derived_class(){
               cout<< "you are in derived class ";
    }
 
};

int main(){
    Derived_class  d;
    return 0;
}

with this code output is : you are in baseclass 1 you are in baseclass 2 you are in derived class

as the constructors are called from base class in the order in which they are written

class Derived_class: public  BaseClass_1, public  BaseClass_2

if i change this line to

  class Derived_class: public  BaseClass_1,public virtual BaseClass_2

we get output as: you are in baseclass 2 you are in baseclass 1 you are in derived class

so the base class 2 constructor is called first, the order is altered , how this happens?

Because the standard says so... Virtual base classes are always constructed first. — Cody Gray - on strike, Dec 20 '20 at 07:20
Virtual base classes are always constructed first---- why so? — user4599, Dec 21 '20 at 04:44
[Because the standard says so!](https://stackoverflow.com/a/27457219) — Cody Gray - on strike, Dec 22 '20 at 07:37

virtual inheritance in c++ order of inheritance

0 Answers0