Destructors in C++

A destructor is a special member function that works just opposite to constructor, unlike constructors that are used for initializing an object, destructors destroy (or delete) the object.

Syntax of Destructor

~class_name()    
{   
   //Some code   
}

Similar to constructor, the destructor name should exactly match with the class name. A destructor declaration should always begin with the tilde(~) symbol as shown in the syntax above.

When does the destructor get called?

A destructor is automatically called when:
1) The program finished execution.
2) When a scope (the { } parenthesis) containing local variable ends.
3) When you call the delete operator.

Destructor Example

#include <iostream>
using namespace std;
class HelloWorld{
public:
  //Constructor
  HelloWorld(){
    cout<<"Constructor is called"<<endl;
  }
  //Destructor
  ~HelloWorld(){
    cout<<"Destructor is called"<<endl;
   }
   //Member function
   void display(){
     cout<<"Hello World!"<<endl;
   }
};
int main(){
   //Object created
   HelloWorld obj;
   //Member function called
   obj.display();
   return 0;
}

Output:

Constructor is called
Hello World!
Destructor is called

Destructor rules

1) Name should begin with tilde sign(~) and must match class name.
2) There cannot be more than one destructor in a class.
3) Unlike constructors that can have parameters, destructors do not allow any parameter.
4) They do not have any return type, just like constructors.
5) When you do not specify any destructor in a class, compiler generates a default destructor and inserts it into your code.