C++ classes: what is the default access specifier for members inside a class definition?

Introduction / Context:
Access control is fundamental to encapsulation. In C++, the default accessibility of members differs between class and struct. Understanding the default helps you avoid unintended exposure of implementation details and enforces safer APIs by default.

Given Data / Assumptions:

• Context: members declared within a class block.
• No explicit access specifier precedes the member declarations.
• We are not discussing inheritance access here, only member access level.

Concept / Approach:

Inside a class, the default access for members is private. Inside a struct, the default is public. This asymmetry is deliberate: class encourages encapsulation by hiding internals unless explicitly exposed, while struct is often used for simple aggregates where public data is acceptable. You can always override defaults by writing explicit public:, protected:, or private: labels.

Step-by-Step Solution:

Verification / Alternative check:

Try accessing a member from outside the class without an explicit public: section; the compiler emits an access error, confirming the default is private for classes.

Why Other Options Are Wrong:

public/protected: not the default in classes.

friend: not an access level for members; it is a relationship granting access to another function/class.

Common Pitfalls:

• Assuming class and struct share the same default; they do not.
• Overusing public data, which weakens encapsulation.

Final Answer:

private