Inheritance - Lecture notes 8 PDF

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Summary

Programming Technique 2: Inheritance Base Class & Derived Class • Base class= parent • Derived class =child • child inherit the members in base class without rewriting them • class FinalExam : public GradedActivity //format for child class ❖ [FinalExam=child, Gradedactivity=base] • 3...

Description

Programming Technique 2: Inheritance

Base Class & Derived Class •

Base class= parent

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Derived class =child

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child inherit the members in base class without rewriting them

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class FinalExam : public GradedActivity //format for child class ❖ [FinalExam=child, Gradedactivity=base]

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3 diff type of inheritance : private, protected and public

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All private member variable of each inherited type is inaccessible by child class

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base class’s constructor is called before the derived class’s constructor

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destructors are called in reverse order, with the derived class’s destructor being called first

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If base class( parent ) has more than 1 constructor ❖ specify it like this >>> Cube( ) : Rectangle( )

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Rectangle constructor will be call first than cube constructor

❖ If the base class has no default constructor, then the derived class must have a constructor that calls one of the base class constructors.

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Base class function can be redefined in derived class

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Derived class can become base class of another class at the same time

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If derived class’s member function has same name as base class member function, it means derived class function redefines base class function

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Redefined class function is DIFFERENT as overloaded function ❖ overloaded has same name but diff parameter ❖ redefined has same name and same parameter

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object of base class will still execute base class function even though it is being redefined by derived class

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If we redefine a function derived from base class in derived class, when we want to call that redefined function, we need to put "class name & object " as parameter. The function we want to call should have the word" virtual" in front of the function for example: virtual char getLetterGrade() const; ❖ this will tell the compiler that this function should be called and not the previous function ❖ put virtual only if the function is defined in the class ❖ The result will based on the function in the class of the object

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Aggregation: ❖ GradedActivity *exam = new PassFailExam(100, 25, 70.0); ❖ cout getScore()...