C++ When to allocate on heap vs stack?

Question

Whilst asking another question (and also before) I was wondering how do I judge whether to create an object on the heap or keep it as an object on the stack? What should I ask myself about the object to make the correct allocation?

Answer 1

Put it on the heap if you have to, the stack if you can.

What kinds of things do you need to put on the heap? Anything of varying length. Any object that might need to be null. Anything that's very large, lest you cause a stack overflow.

Answer 2

Simple answer.

When it goes out of scope, do you want it to hang around and be able to use it?