Multiple Inheritance

[ambar.shome]

Hi,

See this code snippet....

class base1
{
public:
~base1(){cout<<"base1 destructor called"<<endl;}
};

class base2
{
public:
~base2(){cout<<"base2 destructor called"<<endl;}
};

class derived: public base1, public base2
{
public:
~derived(){cout<<"derived destructor called"<<endl;}
};

void main()
{
base2* b2 = new derived();
cout<<"Ambar in UNIX"<<endl;
delete b2;
}

When I executed this on a Solaris machine and it has given following
output:

"base2 destructor called"

but when i tried to execute it has given me run-time error.

at "delete b2".


Can anyone tell me the reason of this type of behaviour of C++?

 

[Victor Bazarov]

See this code snippet....

class base1
{
public:
~base1(){cout<<"base1 destructor called"<<endl;}
};

class base2
{
public:
~base2(){cout<<"base2 destructor called"<<endl;}
};

class derived: public base1, public base2
{
public:
~derived(){cout<<"derived destructor called"<<endl;}
};

void main()

There is no 'void main' in C++.

{
base2* b2 = new derived();
cout<<"Ambar in UNIX"<<endl;
delete b2;
}

When I executed this on a Solaris machine and it has given following
output:

"base2 destructor called"

but when i tried to execute it has given me run-time error.

at "delete b2".


Can anyone tell me the reason of this type of behaviour of C++?

The behaviour is undefined. Deleting an object of a derived class through
a pointer to any of its base classes _without_ a virtual destructor cause
undefined behaviour.

V

 

[msalters]

(e-mail address removed) schreef:

class base1
{
public:
~base1(){cout<<"base1 destructor called"<<endl;}
...

When you're dealing with public inheritance, you should almost
always use virtual destructors. MI doesn't change that.

HTH,
Michiel Salters