uArray

A uC++ macro that allocates a dynamically-sized array on the stack, with deferred per-element construction.

Why?

Standard C++ stack arrays need a compile-time size, and Obj arr[n] requires a default constructor. When the size is only known at runtime and each element needs different constructor arguments, the only standard option is heap allocation — see Stack vs Heap Allocation. uArray works around this while keeping stack semantics (implicit deallocation at scope exit).

{
    cin >> size;
    uArray( Obj, objs, size );      // macro: stack-allocated, size dynamic
    for ( int id = 0; id < size; id += 1 )
        objs[id]( id );              // explicit constructor call per element
    ...
}   // implicit array deallocate at block exit

Each element is raw storage until you invoke its constructor via objs[id](args). Destructors fire automatically when the block exits.