C++ Notes: Classes - Visibility - public and private

Public and Private parts

All members (fields and methods) of a class are private by default (no code outside the class can reference them), whereas fields of a struct are public, meaning that anyone can use them. For example,

struct Product {
   char mfg_id[4];    // 4 char code for the manufacturer.
   char prod_id[8];   // 8-char code for the product
   int  price;        // price of the product in dollars.
   int  qty_on_hand;  // quantity on hand in inventory
};

could be rewritten as a class like this

class Product {
  public:
    char mfg_id[4];    // 4 char code for the manufacturer.
    char prod_id[8];   // 8-char code for the product
    int  price;        // price of the product in dollars.
    int  qty_on_hand;  // quantity on hand in inventory
};

The public and private keywords may be written before any declarations, but it is common to group all public members, then all private members. For example,

class Point {
  public:
    int getX();
    int getY();
    int setX();
    int setY();
    
  private:
    int x;
    int y;
};