C++ Programming Object-Oriented Programming Syllabus

Object-Oriented Programming syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Object-Oriented Programming in C++ Programming, not a summary of it.

1. 1

   Classes and Objects

   3 topics

   • Class Definition
   • Creating Objects
   • Access Specifiers
2. 2

   Constructors and Destructors

   4 topics

   • Default Constructor
   • Parameterized Constructor
   • Copy Constructor
   • Destructor
3. 3

   Inheritance

   3 topics

   • Base and Derived Classes
   • Types of Inheritance
   • Virtual Base Class
4. 4

   Polymorphism

   4 topics

   • Compile-time Polymorphism
   • Runtime Polymorphism
   • Virtual Functions
   • Abstract Classes
5. 5

   Operator Overloading

   3 topics

   • Unary Operator Overloading
   • Binary Operator Overloading
   • Function Call Operator Overloading

Object-Oriented Programming flashcards for C++ Programming

23 of 50 cards from the Object-Oriented Programming deck — real questions with worked answers.

1. In C++, what is a class and what is the syntax to define one?

   A class is a user-defined data type that binds data members and member functions into a single unit (a blueprint for objects). Syntax: $$\texttt{class ClassName \{ ... \};}$$ The definition must end with a semicolon.

2. What are the two main components (members) inside a class definition?

   1. Data members (attributes/variables that hold state). 2. Member functions (methods that define behavior). Together they encapsulate data and the operations on that data.

3. How do you create an object of a class in C++, both on the stack and on the heap?

   Stack (automatic): $\texttt{ClassName obj;}$ Heap (dynamic, using new): $\texttt{ClassName* p = new ClassName;}$ which returns a pointer and must later be freed with $\texttt{delete p;}$

4. How are members accessed through an object versus through a pointer to an object?

   Through an object, use the dot operator: $\texttt{obj.member}$. Through a pointer, use the arrow operator: $\texttt{ptr->member}$, which is shorthand for $\texttt{(*ptr).member}$.

5. What are the three access specifiers in C++ and what does each control?

   public: members accessible from anywhere. private: members accessible only within the class and its friends. protected: members accessible within the class, its friends, and its derived classes.

6. What is the default access specifier for members of a class versus a struct in C++?

   For a class, the default access is private. For a struct, the default access is public. This is the primary difference between class and struct in C++.

7. What is a constructor in C++ and how is it distinguished from ordinary member functions?

   A constructor is a special member function automatically invoked when an object is created, used to initialize it. It has the same name as the class and no return type (not even void).

8. What is a default constructor?

   A default constructor is a constructor that takes no arguments (or has all parameters with default values). It initializes objects when no arguments are supplied, e.g. $\texttt{ClassName();}$. The compiler provides an implicit one if no constructor is declared.

9. When does the compiler NOT provide an implicit default constructor?

   If you define any constructor of your own (e.g., a parameterized constructor), the compiler does not automatically generate a default constructor. You must define one explicitly if you still need it.

10. What is a parameterized constructor and give its purpose?

    A parameterized constructor takes one or more arguments, allowing objects to be initialized with specific values at creation time, e.g. $\texttt{Point(int x, int y);}$. It enables different objects to start with different states.

11. What is a member initializer list and why is it preferred over assignment in the constructor body?

    It initializes members before the constructor body runs, using the syntax $\texttt{Ctor(args) : mem1(v1), mem2(v2) \{ \}}$. It is required for const members, references, and base-class subobjects, and it avoids a redundant default-construct-then-assign step.

12. What is a copy constructor and what is its standard signature?

    A copy constructor creates a new object as a copy of an existing object. Standard signature: $$\texttt{ClassName(const ClassName\& other);}$$ The parameter is passed by const reference to avoid infinite recursion and unnecessary copying.

13. Why must the copy constructor's parameter be passed by reference and not by value?

    Passing by value would itself require a copy to be made, which would call the copy constructor again, leading to infinite recursion. Passing by reference avoids this.

14. Name three situations in which the copy constructor is invoked.

    1. When an object is initialized from another object of the same class. 2. When an object is passed by value to a function. 3. When an object is returned by value from a function. (Also during certain copy-initializations.)

15. What is the difference between a shallow copy and a deep copy?

    A shallow copy copies member values directly, so pointer members share the same memory. A deep copy allocates new memory and duplicates the pointed-to data, so each object owns independent resources. The default copy constructor performs a shallow copy.

16. What is a destructor and what is its syntax?

    A destructor is a special member function automatically called when an object goes out of scope or is deleted, used to release resources. Syntax: $\texttt{\~ClassName();}$ — same name as the class prefixed with a tilde, no arguments, no return type.

17. In what order are constructors and destructors called for an object hierarchy?

    Constructors: base class first, then derived class. Destructors: reverse order — derived class first, then base class. For member objects, they are constructed in declaration order and destructed in reverse.

18. What is the Rule of Three in C++?

    If a class needs a user-defined destructor, copy constructor, or copy assignment operator, it almost certainly needs all three. This is because such classes typically manage a resource (like dynamic memory) requiring consistent copy and cleanup semantics.

19. What is inheritance and what are the base class and derived class?

    Inheritance lets a new class acquire the members of an existing class. The base class (parent) is the one being inherited from; the derived class (child) inherits from it and can add or override members. Syntax: $\texttt{class Derived : public Base \{ \};}$

20. How does the inheritance access mode (public, protected, private) affect inherited members?

    public inheritance: base's public stays public, protected stays protected. protected inheritance: base's public and protected both become protected. private inheritance: base's public and protected both become private. In all cases, base's private members are never directly accessible.

21. List the five types of inheritance in C++.

    1. Single inheritance (one base). 2. Multiple inheritance (multiple bases). 3. Multilevel inheritance (chain: A -> B -> C). 4. Hierarchical inheritance (one base, many derived). 5. Hybrid inheritance (combination of the above).

22. What is multiple inheritance and what classic problem can it cause?

    Multiple inheritance is when a derived class inherits from more than one base class ($\texttt{class C : public A, public B}$). It can cause the diamond problem: ambiguity and duplicate base subobjects when two bases share a common ancestor.

23. What is the diamond problem in C++?

    It occurs when a class D inherits from two classes B and C that both inherit from a common base A. D then contains two copies of A's members, causing ambiguity and duplication. It is resolved using virtual base classes.

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