I require a vector of integers, where I can distinguish between 0 and -0. So far i've come up with the idea of defining a new class called zero_int for this special case..
However, now I can't push both normal integers and the zero_int into the same vector. The solution std::variant has the size of 8 Bytes and I need to retain the size of 4 per variable.. Defining a virtual base class my_int and setting zero_int to be its derived class increases the size of zero_int to 32 Bytes...
I'm aware one could use something like a vector<void*> but I don't know how.. - Also, are objects pointed to by the pointers in a vector of pointers contiguous in memory?? - This is important in this case.
I would appreciate any suggestions on how to solve this
The solution std::variant has the size of 8 Bytes and I need to retain the size of 4 per variable..
That's impossible, unless you don't mind losing one possible non-zero int value.
Which brings us to the "obvious" solution: treat 0 as -0, and every positive number as itself minus one.
vec[i]: -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5
my "value": -5 -4 -3 -2 -1 -0 +0 +1 +2 +3 +4
(Or do it the other way around, which gives you symmetry in positive and negative ranges; whatever you like.)
Make whatever class wraps your vector handle this "mapping" in whatever way is appropriate for your project.
are objects pointed to by the pointers in a vector of pointers contiguous in memory??
No.
You don't want more indirection here.
Someone will suggest using floating-point, since IEEE 754 supports signed zero. However, I submit that switching to floating-point for representing real numbers in any case is likely to introduce more problems than it solves.