To reference the outer class from within a nested class in C++, you can use the scope resolution operator (::) followed by the outer class name.

Here is an example to illustrate how to reference the outer class from within a nested class:

#include <iostream>

class OuterClass {
private:
    int outerMember;

public:
    class NestedClass {
    public:
        void displayOuterMember(OuterClass& outer) {
            std::cout << "Outer class member: " << outer.outerMember << std::endl;
        }
    };
};

int main() {
    OuterClass outer;
    OuterClass::NestedClass nested;

    nested.displayOuterMember(outer);

    return 0;
}

In the above example, we have an OuterClass that contains a nested class NestedClass. Inside NestedClass, we define a member function displayOuterMember that takes an instance of the outer class as a parameter.

In the main function, we create an object of the outer class OuterClass and an object of the nested class OuterClass::NestedClass. We then call the displayOuterMember function on the nested object, passing the outer object as an argument.

Inside the displayOuterMember function, we use the outer parameter to access the outerMember variable of the outer class.

By using the scope resolution operator (::), we can reference the outer class from within the nested class and access its members and methods.

Remember, when referencing the outer class from within a nested class, the outer class must be fully defined before the nested class can be used.

#C++ #NestedClasses