obj *x = new obj[5]; //
x = renew obj[x,7]; // Construct two new objs.
printf("x has %d objs", x.size()); // Print the size of the array.
x = renew obj[x,3]; // Destruct four objs.
delete [] x; // Destruct the remaining three objs.
obj *x = (obj *)malloc(sizeof(obj)); // Manually allocate object.
x->obj(); // Manually call constructor.
x->~obj(); // Manually call destructor.
free(x); // Manually free object.
obj *x = (obj *) ::operator new(sizeof(obj)); // Allocate memorynew (x) obj; // placement newx->~obj(); // Destructor call.::operator delete(x); // Deallocate memoryQuote:Original post by Krylloan
Does anyone know how to resize an array constructed using new[], or get the current array size?
Quote:Original post by Krylloan
Secondly, does anyone know how to force-call a constructor or destructor on any object without calling the allocation functions or modifying the object's internal functions/data.
#include <new>struct foo { int i; foo(int j): i(j) {}};int main() { void* buf = ::operator new(sizeof(foo)); // allocate only foo* f = new(buf) foo(30); // construct only, placement new f->~foo(); // destruct only, must be done for user-defined types ::operator delete(buf); // de-allocate only}
OBJECT* pObject = NULL;INT nObjectNum = 10;pObject = (OBJECT*)realloc(pObject, nObjectNum * sizeof(OBJECT));Quote:Original post by WanMaster
You can use realloc:OBJECT* pObject = NULL;INT nObjectNum = 10;pObject = (OBJECT*)realloc(pObject, nObjectNum * sizeof(OBJECT));
Quote:Original post by Fruny
If your objects have constructors/destructors, realloc() could leave you in deep doo-doo.
class obj { public: obj() : x(0) {} ~obj() {} int x;};int main() { obj *x = (obj *) ::operator new(sizeof(obj)); // Allocate memory new (x) obj; // placement new /* Other tries: new (x) obj; new (*x) obj; new (x) obj(); new (*x) obj(); obj *y = new (x) obj; */ x->~obj(); // Destructor call. ::operator delete(x); // Deallocate memory return 0;}class obj { public:// obj() : x(0) {} obj(int y) : x(y) {} ~obj() {} int x;};int main() { void* buf = ::operator new(sizeof(obj)); // allocate only obj* f = new(buf) obj(5); // construct only, placement new f->~obj(); // destruct only, must be done for user-defined types ::operator delete(buf); // de-allocate only return 0;}Quote:As for vectors, I've looked at them a bit, but I'm using custom allocators and things get a little tricky there.
