Constructor vs Destructor

Constructors and destructors control object lifetime.

Feature	Constructor	Destructor
Purpose	Initialize object	Clean up object
Name	Same as class	Same as class with `~`
Return type	None	None
Parameters	Can have parameters	Cannot have parameters
Overloading	Can be overloaded	Cannot be overloaded
Call timing	When object is created	When object is destroyed
In inheritance	Base before derived	Derived before base
Common use	set valid starting state	release resources

Lifecycle Example

#include <iostream>

class Demo {
public:
    Demo() {
        std::cout << "Constructor\n";
    }

    ~Demo() {
        std::cout << "Destructor\n";
    }
};

int main() {
    Demo object;
}

Output:

Constructor
Destructor

Inheritance Order

Construction:

Base constructor -> Derived constructor

Destruction:

Derived destructor -> Base destructor

Viva Answer

A constructor initializes an object when it is created, while a destructor cleans up an object when it is destroyed. Constructors can be overloaded and take parameters; destructors cannot take parameters and cannot be overloaded.

Quick Check

Which runs first: constructor or destructor?
Can constructors be overloaded?
Can destructors be overloaded?
What is destruction order in inheritance?