delete partial memory of the pointer

Question

Is there any way i can delete the partial memory of the pointer.? for example

char *c = new char[1000];
sprintf(c,\"this is it\");

As it can b

Answer 1

Well, allocate another memory block with the precise size required for the data, copy the data there and free the original (exceedingly large) memory block. Done.

Answer 2

Not directly. The best you can do in C++ is to make a new copy that's the right size and delete the old one. There's no analog of C's realloc.

Answer 3

Unless your system is a RAM-restricted embedded system, why bother? Just use ginormous buffers and include a 'dataLen' int.