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Constructors and Destructors
Features of a Constructor
A constructor is a special member function that is automatically called when an object is created.
Main Features
- Has the same name as the class
- No return type (not even
void) - Called automatically when an object is instantiated
- Used to initialize data members
- Can be overloaded (default, parameterized, copy, move)
- Can use an initializer list
- Can have default arguments
- Usually declared public
- Cannot be inherited, but base-class constructors are called during object creation
Features of a Destructor
A destructor is a special member function that is automatically called when an object is destroyed.
Main Features
- Name is the class name prefixed with
~ - No return type and no parameters
- Called automatically when an object goes out of scope or is deleted
- Used to release resources (memory, files, locks)
- Only one destructor per class (cannot be overloaded)
- Can be virtual (important for polymorphism)
- Called in reverse order of construction
- Usually declared public
Constructor vs Destructor (Quick Comparison)
| Feature | Constructor | Destructor |
|---|---|---|
| Purpose | Initialize object | Clean up resources |
| When called | Object creation | Object destruction |
| Parameters | Allowed | Not allowed |
| Overloading | Allowed | Not allowed |
| Inheritance | Not inherited | Not inherited |
| Virtual | No (usually) | Yes (often needed) |
One-Line Exam Summary
- A constructor initializes an object automatically when it is created.
- A destructor cleans up resources automatically when the object is destroyed.
Constructors and Destructors
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