Why destructor is used when delete is there?

When delete is used to deallocate memory for a C++ class object , the object’s destructor is called before the object’s memory is deallocated (if the object has a destructor). If the operand to the delete operator is a modifiable l-value, its value is undefined after the object is deleted.

Destructors are used to destroy the objects created by the Constructors when they are not needed anymore to release the memory . They are special member functions and called automatically by C++. Compiler to free up the memory when there is no user-defined destructor in the program.

In object-oriented programming, a destructor (sometimes abbreviated dtor) is a method which is invoked mechanically just before the memory of the object is released. … Its main purpose is to free the resources (memory allocations, open files or sockets, database connections, resource locks, etc.)