Question

Can i make an object in C++ specifying its memory address explicitly? This is because i am having separate ids for each of my entities (the objects). So if i can do this, i will be able to traverse through all my objects by mere pointer additions.
Consider:
I have an object with memory location x.
I want to create the next object with memory location x+(the unique id of the next object)*K
where K is the constant gap between two objects(say)

Answer 1

You can specify the memory using the placement new operator.

So if i can do this, i will be able to traverse through all my objects by mere pointer additions.

Not really. Disregard answers that tell you to do this! You can’t do pointer arithmetics outside of an array. Just because you have 2 objects o1 and o2, one located at 0x4 and the other at 0x5, it doesn’t mean that &o1 + 1 will yield &o2. In fact, it’s undefined behavior.

For this to work as expected, you can allocate the memory dynamically, or, better yet, use a std::vector and use iterators. (that’s what they are for)