Differences between string headers.

Question

I'm a bit confused, for me it seems the same, I have this headers:

#include<string>
#include<string.h>
#include<cstring>

what are the differences between this headers? which one are C++ header and C header?
is it better to use C++ headers instead C?

besides, I'm learning how to get a string from the user, why Can I use std::string without the headers above? or Do I need to include any header above to use std::string?

Answer 1

string is the C++ header, which contains std::string
cstring is the C++ version of the C header
string.h is the C header