Constructor and Types of Constructors

Constructor and Types of Constructors

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  Topic Constructor and Typesof Constructor
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  Contain • Overview ofConstructor • Properties of Constructor • Types of Constructor 1. Default Constructor 2. Parameterized Constructor 3. Copy Constructor
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  Constructor • A constructoris a “special” member function which initializes the objects of class.
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  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.
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  Types of Constructors •There are mainly three types of constructors as follows: 1. Default Constructor 2. Parameterized Constructor 3. Copy Constructor
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  Default Constructor • Defaultconstructor 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.
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  Example class integar { int m,n; public: integer()// Default constructor { m=n=0; } };
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  Parameterized Constructor • Constructorsthat 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.
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  Example class integer { int m,n; public: integer(intx,int y) // Parameterized constructor { m =x; n=y; } };
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  Copy Constructor • Acopy 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.
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  Example class integer { int m,n; public: integer(rectangle &x) // Copy constructor { m = x.m; n = x.n; } };
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  References
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  Thank You #include<iostream> using namespacestd; int main() { cout << “Thank You”; return 0; }