Also read : Can a constructor be private in C++ ?
Predict the output of following programs.
The above program compiles and runs fine. Hence, we can say that : It is not compiler error to create private destructors.
Now, What do you say about below program.
The above program fails in compilation. The compiler notices that the local variable ‘t’ cannot be destructed because the destructor is private.
Now, What about the below program?
The above program works fine. There is no object being constructed, the program just creates a pointer of type “Test *”, so nothing is destructed.
Next, What about the below program?
The above program also works fine. When something is created using dynamic memory allocation, it is programmer’s responsibility to delete it. So compiler doesn’t bother.
In the case where the destructor is declared private, an instance of the class can also be created using malloc() function. Same is implemented in below program.
However, The below program fails in compilation. When we call delete, destructor is called.
We noticed in the above programs, when a class has private destructor, only dynamic objects of that class can be created. Following is a way to create classes with private destructors and have a function as friend of the class. The function can only delete the objects.
What is the use of private destructor?
Whenever we want to control destruction of objects of a class, we make the destructor private. For dynamically created objects, it may happen that you pass a pointer to the object to a function and the function deletes the object. If the object is referred after the function call, the reference will become dangling. See this for more details.
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