Множественное наследование

#include <iostream>
#include <conio.h>
#include <string>
using namespace std;
 
class B1{
 int a;
public:
 B1() { };
 B1(int x) { a=x; }
 void show_B1() { cout <<"B1=   "<< a << "\n"; }
};
 
class B2{
 int b;
public:
 B2() { };
 B2(int y) { b=y; }
 void show_B2() { cout <<"B2=   "<< b << "\n"; }
};
 
class D1: public B1 {
 int c;
public:
 D1(int x, int z) : B1(z) { c=x;};
 void show_D1() { cout <<"D1=  "<< c << "\n"; show_B1();}
};
 
class D2: private D1, public B2 {
 int f;
public:
 D2(int x, int y, int z, int i, int j) : D1(y,z), B2(i,j) { f=x;}
 void show_D2() { cout <<"D2=  "<< f << "\n"; show_D1(); show_B2();}
};
 
class D3: public D2{
 int e;
public:
 D3(int x, int y) : D2(y) { e=x;};
 void show_D3() { cout <<"D3=  "<< e << "\n"; show_D2();}
};
 
int main() {
D3 temp(100,200,300,400,500);
cout << "D3 temp(100,200,300,400,500);\n";
cout<< "\Иерархия* D3: \n";
temp.show_D3();
getch();
return 0;
}

D3(int x, int y) : D2(y) { e=x;};