abstraction.md

Abstraction

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Abstraction

• Interface
  • The public part of a class
    • Member function - obvious
    • Non-member function
    • Member types
    • Member fields
    • Template parameters
    • Specializations
  • Example: std::vector on cppreference.com
  • The private part (implementation) is unknown
• Object Oriented Design (OOD)

Make interfaces easy to use correctly and hard to use incorrectly

-- Scott Meyers, Effective C++

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Bad interface example

// A date class which is easy to use but also easy to use wrong.
class Date {
    public:
        Date(int month, int day, int year);
        ...
};

// Both are ok, but some european programmer may use it wrong,
// because european time format is dd/mm/yyyy instead of mm/dd/yyyy.
Date d(3, 4, 2000);
Date d(4, 3, 2000);