What is the difference between delete and free in C++?

In C++, both delete and free are used to release memory, but there are some important distinctions.

1. “delete is a C++ keyword used to release dynamically allocated memory by the new operator. It will call the object’s destructor to clean up resources and free the memory. On the other hand, free is a C library function used to release dynamically allocated memory by malloc, calloc, or realloc. It does not call the object’s destructor, but simply frees the memory.”
2. Delete is an object-oriented concept that can correctly handle objects with virtual functions and inheritance relationships. It will automatically call the destructors of both the base class and derived class. On the other hand, free merely releases memory without considering the type or inheritance relationship of the object.
3. The ‘delete’ operator can be overloaded to call the appropriate destructor based on the object type, while ‘free’ is a library function and cannot be overloaded.
4. The delete operator is only used to release memory allocated with the new operator, while the free function can be used to release memory allocated with malloc, calloc, and realloc.

In general, when allocating memory in C++ with new, you should release it with delete; and when allocating memory with malloc or calloc, you should release it with free. Using the corresponding release function ensures proper memory release and handling of object destructors.