multiple inheritance

[ohren]

Hello,

I have an inheritance hierarchy like this:

class Person{
...
}
 
class HandlerSubjects{
         public:
                   virtual void setSubject(string);
.....
}
 
 
class Estudient: public Person,public HandlerSubjects{
 
....
 
}
 

in main I have:

Person* p;
*p=new Estudient();

How Could I call the member function setSubject() ?

p->setSubject("sc ience"); it is not possible.

Thank you

[weaknessforcats]

This code:

Person* p;
*p=new Estudient();
How Could I call the member function setSubject() ?

p->setSubject("sc ience"); it is not possible.

will work fine once you fix the error: p has to be an Estudient* and nort a Person*.

There is no setSubject() in Person.

[ilikepython]

Hello,

I have an inheritance hierarchy like this:

class Person{
...
}
 
class HandlerSubjects{
         public:
                   virtual void setSubject(string);
.....
}
 
 
class Estudient: public Person,public HandlerSubjects{
 
....
 
}
 

in main I have:

Person* p;
*p=new Estudient();

How Could I call the member function setSubject() ?

p->setSubject("sc ience"); it is not possible.

Thank you

Also, there shouldn't be a dereferencing sign when you assign to p. It should be this:

p = new Estudient();
 

[ohren]

Also, there shouldn't be a dereferencing sign when you assign to p. It should be this:

p = new Estudient();
 

Yes, but I have also the class Teacher that inherits from Person but not from HandlerSubjects , and I need to Know whit a pointer Person* if the object that points inherits or not from HandlerSubjects . How could I Know that?

[weaknessforcats]

What are you trying to do??

Multiple inheritance is not a beginner's thing. It's hard to do and you have you know your C++ in order to so it.

I don't think a Teacher can inherit from Person:
1) The Teacher has methods that are not appropriate to Person
2) Because of (1), you have to create Teacher objects and use Teacher*.

If you are trying to be object-orented, then the base class must have the methods used by the derived classes. That means you need to design your base class first. Then you write all of your code using base class pointers or references. Then you get that working.

Now you can derive a Teacher from Person and pass the address of the Teacher to the code expecting Person* or Person&. If you have done your design work, the program wwill compile and run with no changes required. Otherwise, your compile will fail.

I suggest writing the hierarchy on paper (complete with method names and which ones are virtual) before you start coding.