![Dynamic memory
Operators new and new[]
The new operator offers dynamic storage allocation similar to
the standard library function malloc.
Throws an exception when memory allocation fails.
pointer = new type
pointer = new type [number_of_elements]
int * b;
b = new int [5];
Operators delete and delete[]
delete pointer;
delete [] pointer;
Example](https://image.slidesharecdn.com/unit-ii-151229061048/85/Unit-ii-14-320.jpg)
Unit ii
- 2. Structure Definitions struct time { int hour; int min; int second; } Accessing members of structure time t; cout<<t.hour; time * timeptr; Using pointers timeptr = &t; cout<<timeptr->hour; (*timeptr).hour; Example
- 3. Classes and Objects A class can be described as a collection of data members and member functions. Functions are called member functions and define a set of operations that can be performed on the data members of the class. The association of data and member functions are called encapsulation.
- 5. Class objects The process of creating objects(variables) of the class is called class instantiation. Necessary resources are allocated only when the class is instantiated. The syntax is as follows: Class className ObjectName….. Ex: class student s1;
- 6. Accessing Class members Class members are accessed using member access operator , dot(.) Syntax : ObjectName.Datamember; Example: Student s1; s1.rollno; s1.printdetails();
- 7. Defining member functions Member functions of the class can be defined in any one of the following ways Inside the class specification Outside the class specification
- 8. Member functions outside the class body Example
- 9. Access specifiers Private: The private members of a class have strict access control. Only the member functions of the same class can access these members. It prevents accidental modifications of the data members. class person { private: int age; int getage(); }; Person p1; p1.age = 10; // cannot access private data p1.getage(); // cannot access private function
- 10. Public members The members of a class which are visible outside the class are declared in public section. class person { public: int age; int getage(); }; Person p1; p1.age = 10; // can access public datat p1.getage(); // can access public function
- 11. Protected members The access control of protected members is similar to private members and has significance to inheritance. Empty classes; Class xyz{}; Class Empty {};
- 12. Constructors and Destructors Constructors: The constructor gets called automatically for each object that has just got created. It appears as member function of each class, whether defined or not. It has same name as the class. It may or may not take parameters . It does not return anything The prototype is Class name(parameter list); Example
- 13. Parameterized constructors Constructors with arguments are called parameterized constructors. Example
- 14. Dynamic memory Operators new and new[] The new operator offers dynamic storage allocation similar to the standard library function malloc. Throws an exception when memory allocation fails. pointer = new type pointer = new type [number_of_elements] int * b; b = new int [5]; Operators delete and delete[] delete pointer; delete [] pointer; Example
- 15. Destructor When an object is no longer needed it can be destroyed. A class can have a member function called destructor which is invoked when an object is destroyed. Example
- 17. Constructors with dynamic operations Example 2
- 18. Copy constructor
- 19. The copy constructor is a special type of parameterized constructor. It copies one object to another. It can be called when an object is created and equated to an existing object at the same time. Vector v1(5), v2(5); v1= v2; // operator = invoked vector v3 = v2; // copy constructor is invoked. Vector v3(v2) vector *ptr = new vector(v1);
- 20. Passing Objects as Arguments Methods Pass by value Example Pass and return by reference Example Array of objects
- 21. this pointer The this pointer points at the object with respect to which the function was called. this pointer is always a constant pointer. The compiler converts the class into a structure with only data members. class dist { int feet,inch; public: int getfeet(); int getinch(); } struct dist { int feet, inch; }; int getfeet(dist * const); int getinch(dist * const);
- 22. int dist::getfeet() { Return feet; } int getfeet(dist * const this) { return this->feet; }
- 23. OPERATOR OVERLOADING Operator overloading feature of C++ is one of the methods of realizing polymorphism. Operator overloading helps in Extending capability of operators to operate on user defined data. Data conversion Operator overloading extends the semantics of an operator without changing its syntax.
- 25. Unary operator overloading Example with member function Example with operator overloading Operator keyword The keyword operator facilitates overloading of the C++ operators.
- 26. Operator return values idx1 = idx2++; Example Binary Operator overloading
- 27. Arithmetic operators Adding two objects of a class Direct Addition Overloaded + operator String Example
- 28. Comparison operators Example Arithmetic assignment operators
- 29. Data conversion
- 30. Example
- 31. Conversion between objects of different classes. ClassA objecta; ClassB objectb; objecta = objectb; Conversion routine in the source object’s class is implemented using an operator function In objecta= objectb, objectb is the source object of classB
- 32. Conversion between objects of different classes. Example
- 33. Conversion routine in destination object: Constructor function Example
- 34. Overloading with friend functions Example Example 2
- 35. Inheritance Inheritance is a technique of organizing information in a hierarchical form. Inheritance allows new classes to be built from older and less specialized class. Classes are created by first inheriting all the variables and behavior defined by some primitive class and then adding specialized variables and behaviors. Inheritance allows code reusability.
- 37. Base class and derived class
- 39. Example
- 43. Constructors Zero argument constructor in base and derived class Example Parameterized constructors in base and derived classes Example Parameterized constructor in derived class Example
- 44. Multilevel Inheritance Derivation of a class from another derived class is called multilevel inheritance. Example Constructor Example
- 45. Multiple Inheritance Example Example
- 47. Multipath Inheritance The form of inheritance which derives a new class by multiple inheritance of base classes, which are derived earlier form the same base class is known as multipath inheritance. Example
- 48. Problems with multipath inheritance: Ambiguity due to duplicate copies of members inherited from the base class. Virtual Base class is used to solve the ambiguity issue in multipath inheritance.
- 50. Write a program to implement hybrid inheritance shown in the diagram. Consider necessary details for all the classes.