C++ placement new

Question

Sorry if this question will sound stupid, but I\'m just starting to learn C++ and there is something confusing me about the placement new

I\'ve been reading C++ Prim

Answer 1

char buffer[BUF]; is just some memory. There's no type information attached to the bytes composing buffer. Only the compiler knows, that this memory region is supposed to hold characters. You could use any type, even double:

double buffer[BUF];
double *pd1 = new (buffer) double[N];