Is comparison of const_iterator with iterator well-defined?

Question

Consider the following code:

#include 
#include 

int main()
{
    std::vector vec{1,2,3,5};
    for(auto it=vec.cbe         


        

Answer 1

See §23.2.1, Table 96:

X::iterator

[...]

any iterator category that meets the forward iterator requirements.

convertible to X::const_iterator

So, yes, it is well-defined.