delete (C++)

In the C++ programming language, the delete operator returns memory allocated by new back to the heap. A call to delete must be made for every call to new to avoid a memory leak. After calling delete the memory object pointed to is invalid and should no longer be used. Many programmers assign 0 (null pointer) to pointers after using delete to help minimize programming errors. Note, however, that deleting a null pointer has no effect, so it is not necessary to check for a null pointer before calling delete.

Example code snippet: <source lang="cpp"> int *p_var = 0; // new pointer declared p_var = new int; // memory dynamically allocated

/* ....... other code ........*/

delete p_var; // memory freed up p_var = 0; // pointer changed to 0 (null pointer) </source> Arrays allocated with new [] can be similarly deallocated with delete []: <source lang="cpp"> int size = 10; int *p_var = 0; // new pointer declared p_var = new int [size];// memory dynamically allocated

/* ....... other code ........*/

delete [] p_var; // memory freed up p_var = 0; // pointer changed to 0 </source>