The placement syntax for operator new( ) can be used only if you have overloaded the allocation operator with the appropriate arguments. You can use the placement syntax when you want to use and reuse a memory space which you set up once at the beginning of your program. 

When you use the overloaded operator new( ) to specify where you want an allocation to be placed, you are responsible for deleting the allocation. Because you call your version of the allocation operator, you cannot depend on the global ::operator delete( ) to do the cleanup. 

To release memory, you make an explicit call on the destructor. This method for cleaning up memory should be used only in special situations and with great care. If you make an explicit call of a destructor before an object that has been constructed on the stack goes out of scope, the destructor will be called again when the stackframe is cleaned up.