C++ Constructors - Unit III

Study Notes

A constructor is a special member function called automatically upon object creation.
Its primary function is to initialize data members of a class with either default or user-provided values.

Same Name as Class: Constructors share the same name as the class they belong to.
No Return Type: They do not return any value, not even void.
Automatically Called: Invoked automatically when an object of the class is instantiated.

Default Constructor: Takes no parameters. Automatically provided by the compiler if not defined, initializes data members to default values.
Parameterized Constructor: Accepts parameters to initialize object data members with specific values, adding flexibility in object creation.
Copy Constructor: Creates a new object as a copy of an existing object, important for resource management and avoids issues like double deletion.
Dynamic Constructor: Allocates memory dynamically at runtime using operators like new, useful for variable resource requirements.
Default Arguments Constructor: Allows setting default values for parameters, simplifying the creation of objects with optional initial values.

Automatic Initialization: Objects are initialized upon creation, preventing undefined states.
Encapsulation: Initialization logic is contained within the class, minimizing the need for external initialization.
Overloading Support: Multiple constructors enable various initialization methods based on specific use cases.
Resource Management: Works together with destructors for effective memory and resource management.
Code Reusability: Enables different ways of creating objects, enhancing flexibility and reducing code duplication.

Refers to initializing objects at runtime using values available only during execution, suitable for unpredictable data requirements.

A destructor cleans up resources when an object is destroyed, indicated by a tilde (~) before the class name.
Automatically invoked when an object goes out of scope or is deleted, responsible for freeing resources like memory or file handles.

Same Name as Class: Uses the class name prefixed with a tilde (~).
No Parameters: Do not take arguments or return values as they are automatically called.
One Per Class: Only one destructor can exist per class.
No Explicit Invocation: Cannot be called by the programmer, only invoked implicitly.
Order of Destruction: Destroys components in reverse order of their initialization.

Purpose: Constructors initialize an object; destructors release resources.
Names: Constructors have the same name as the class; destructors are prefixed with a tilde (~).
Return Type: Both have no return type.
Call Mechanism: Constructors are called upon object creation; destructors are called when the object is destroyed.
Overloading: Constructors can be overloaded; destructors cannot.
Default Behavior: Compiler provides default implementations for both, if not explicitly defined.

Constructors are typically used for setting up resources and initializing member variables.
Destructors are utilized for releasing resources, closing files, or cleaning up memory.