Access Specifiers

Access Specifiers

An access specifier is a keyword inside a class that controls who can use the members declared after it. There are three: public, private, and protected.

Setting up sections

Sections are introduced with a semicolon followed by the keyword and a colon:

class Account {
public:
  double balance;      // reachable from outside
private:
  int pin;             // hidden from outside
protected:
  int owner;           // reachable by derived classes
};

A section stays in force until the next specifier.

What each keyword means

• public: members can be used from anywhere the object is visible.
• private: members are hidden from outside the class; only the class's own code (and friends) can touch them.
• protected: like private, but derived classes can also reach them.

The default is private

In a class, members are private by default. The class author must deliberately open them up with public:. That keeps the class's internals safe by default.

TL;DR

• The three access specifiers are public, private, and protected.
• In a class the default is private.
• A section stays active until the next specifier.
• public opens, private hides, protected shares with derived classes only.