which way to access a base class function or variable

-------

I m a student. Today I Give the Interview and tell me something new about inheritance

I said the derived class can not access the base class property or field because below program prove that is why I tell the derived class can not access the base class property or field:

using namespace std;
#include
class baseclass
{
public:
int a;
baseclass()
{
std::cout << "baseclass\n";
}
};
class deriveclass: public baseclass
{
public:
deriveclass()
{
std::cout << "derived class\n";
}
};
int main()
{
baseclass * a=new baseclass(); //ok
deriveclass * b=new deriveclass(); //ok
baseclass * aa=new deriveclass(); //ok
deriveclass * bb=new baseclass(); //not ok
return 0;
}

Link:https://onlinegdb.com/SyfhRDF_U

error:

main.cpp: In function ‘int main()’: main.cpp:30:36: error: invalid conversion from ‘baseclass*’ to ‘deriveclass*’ [-fpermissive] deriveclass * bb=new baseclass(); //not ok

then Interviewer tells me which way to access the base class function or variable?

help?

3 Replies

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Rajanikant Hawaldar6y ago
Accepted answer
int a is public in base so it can be accessed in derived class. Please go through below links to understand access spacifier or modifiers. https://www.learncpp.com/cpp-tutorial/115-inheritance-and-access-specifiers/ https://www.learncpp.com/cpp-tutorial/11-6a-calling-inherited-functions-and-overriding-behavior/
-------6y ago
Thanks, man provide the beautiful link for the explanation thanks again
Rajanikant Hawaldar6y ago
deriveclass * bb=new baseclass(); //This is wrong that's why your getting error because your not aware of polymorpism/Inheritence concept please go below link to understand polymorpism/Inheritence. This tutorial explained with C# program but concept is same both C++ and C# object oriented. https://youtu.be/4a_iTOtGhM8 https://youtu.be/OLTk0xAVY00