C++ Constructor destructor
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The document discusses different types of constructors in C++ classes: 1. Default constructors are created by the compiler if no constructor is defined, and have no parameters. They initialize member variables. 2. Parameterized constructors allow passing different initialization values to objects, by passing arguments to the constructor. 3. Copy constructors copy the values of data members from one object to another by taking an object as a parameter. They are used to initialize a new object with the same values as an existing object.
C++ Constructor destructor
- 2. The Class Constructor: A class constructor is a special member function of a class that is executed whenever we create new objects of that class. Unlike normal functions, constructors have specific rules for how they must be named: 1) Constructors should always have the same name as the class (with the same capitalization) 2) Constructors have no return type (not even void) A constructor that takes no parameters (or has all optional parameters) is called a default constructor.
- 3. Here is an example of a class that has a default constructor: class A { int x; public: A(); //Constructor };
- 4. Constructors can be defined either inside the class definition or outside class definition using class name and scope resolution :: operator. class A { int x; public: A(); //Constructor }; A::A() // Constructor definition { i=1; }
- 5. Constructors are of three types : 1. Default Constructor 2. Parametrized Constructor 3. Copy COnstructor Types of Constructors
- 6. Default Constructor Default constructor is the constructor which doesn't take any argument. It has no parameter Syntax : class_name () { Constructor Definition } Example : class Cube { int side; public: Cube() { side=10; } }; int main() { Cube c; cout << c.side; } Output : 10
- 7. A default constructor is so important for initialization of object members, that even if we do not define a constructor explicitly, the compiler will provide a default constructor implicitly.
- 8. Parameterized Constructor These are the constructors with parameter. Using this Constructor you can provide different values to data members of different objects, by passing the appropriate values as argument Example : class Cube { int side; public: Cube(int x) { side=x; } }; int main() { Cube c1(10); Cube c2(20); Cube c3(30); cout << c1.side; cout << c2.side; cout << c3.side; } OUTPUT : 10 20 30
- 9. Copy Constructor These are special type of Constructors which takes an object as argument, and is used to copy values of data members of one object into other object.