1. OOP

Object-Oriented Programming

Object-oriented design technique using C++ Class

Contents

• 00. C++ Tutorial
• 01. Defining a Class
• 02. Using a Class
• 03. Operation overloading
• 04. Inheritance
• 05. Polymorphism
• 06. Templates
• 07. Exception Handling

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Priciples

• Encapsulation (캡슐화)
  • Hiding implementation details, only exposing the "public interface"
• Abstraction (추상화)
  • Selecting data to show only the relevant details to the object
• Inheritance (상속성)
  • The ability to acquire some/all properties of another object
• Polymorphism (다형성)
  • Provision of a single interface to entities of different types

Goals

• Robustness
  • We want software to be capable of handling unexpected inputs that are not explictly defined for its application.
• Adaptabillity (≒ Portabillity)
  • Software needs to be able to evolve over time in response to changing conditions in its environment.
• Reusabillity
  • The same code should be usable as a component of different systems in various applications.

Object-Oriented Software Design

• Responsibilities
  • Divide the work into different actors, each with a different responsibility.
• Independence
  • Define the work for each class to be as independent from other classes as possible.
• Behaviors
  • Define the behaviors for each class carefully and precisely, so that the consequences of each action performed by a class will be understood by classes that interact with it.

Defining and Using a Class

class ClassName {
Access specifier:
  Data members;
  Member functions() { }
};

Access Specifiers

class MyClass {
public:       // public access specifier
  MyClass();  // constructor
  int x;      // public attribute

private:      // private access specifier
  int y;      // private attribute

protected:    // protected access specifier
  int z;      // protected attribute
};

• public
  • Members are aceessible from outside the class.
• private
  • Members cannot be accessed (or viewed) from outside the class. (독립성을 높이는 설계)
• protected
  • Members cannot be accessed from outside the class, however, they can be accessed in inherited classes.

Example

class Student {
public:
  string name;
  int id;
  float gpa;
  void outputInfo();
private:
  bool scholarship;
  void calcGPA();
};

Student summaCumLaude

• Syntax : class_name instance_name;
• Variable summaCumLaude is an instance of the class Student.
• It is an object of the type Student.