What is difference between malloc()/free() and new/delete

malloc allocates memory for object in heap but doesn’t invoke object’s constructor to initiallize the object. new allocates memory and also invokes constructor to initialize the object. malloc() and free() do not support object semantics.

Does not construct and destruct objects string * ptr = (string *)(malloc (sizeof(string))) Are not safe Does not calculate the size of the objects that it construct Returns a pointer to void int *p = (int *) (malloc(sizeof(int))); int *p = new int; Are not extensible new and delete can be overloaded in a class “delete” first calls the object’s termination routine (i.e. its destructor) and then releases the space the object occupied on the heap memory. If an array of objects was created using new, then delete must be told that it is dealing with an array by preceding the name with an empty []:-

Int_t *my_ints = new Int_t[10];

…

delete []my_ints;