Constructor and Types of Constructors
- 2. Topic Constructor and Types of Constructor
- 3. Contain • Overview of Constructor • Properties of Constructor • Types of Constructor 1. Default Constructor 2. Parameterized Constructor 3. Copy Constructor
- 4. Constructor • A constructor is a “special” member function which initializes the objects of class.
- 5. Properties of Constructor • Constructor is invoked automatically whenever an object of class is created. • Constructor name must be same as class name. • Constructors should be declared in the public section because private constructor cannot be invoked • outside the class so they are useless. • Constructors do not have return types and they cannot return values, not even void. • Constructors cannot be inherited, even though a derived class can call the base class constructor. • Constructors cannot be virtual. • An object with a constructor cannot be used as a member of a union. • They make implicit calls to the operators new and delete when memory allocation is required.
- 6. Types of Constructors • There are mainly three types of constructors as follows: 1. Default Constructor 2. Parameterized Constructor 3. Copy Constructor
- 7. Default Constructor • Default constructor is the one which invokes by default when object of the class is created. • It is generally used to initialize the value of the data members. • It is also called no argument constructor.
- 8. Example class integar { int m,n; public: integer() // Default constructor { m=n=0; } };
- 9. Parameterized Constructor • Constructors that can take arguments are called parameterized constructors. • Sometimes it is necessary to initialize the various data elements of different objects with different values when they are created. • We can achieve this objective by passing arguments to the constructor function when the objects are created.
- 10. Example class integer { int m,n; public: integer(int x,int y) // Parameterized constructor { m =x; n=y; } };
- 11. Copy Constructor • A copy constructor is used to declare and initialize an object from another object. • For example, integer(integer &i); OR integer I2(I1); • Constructor which accepts a reference to its own class as a parameter is called copy constructor.
- 12. Example class integer { int m, n; public: integer(rectangle &x) // Copy constructor { m = x.m; n = x.n; } };
- 13. References
- 14. Thank You #include<iostream> using namespace std; int main() { cout << “Thank You”; return 0; }