Question

class A
{
    A a;//why can't we do this in C++ but it is allowed in Java?
};

Using this question, i came to know why it is not allowed in C++ but why is it allowed in java? According to same argument of not knowing the memory size while compilation, it should not be allowed in Java as well.

Answer 1

In Java, if you have A a;, a is a reference to an object of class A. In C++, it’s not a reference, it’s a complete object.

So the resulting object in C++ would be of infinite size, which isn’t very practical.