我如何使用 unordered_map<string::iterator, string> ?</string::iterator,>

Question

I have a function with the following signature:

void findDotStars(unordered_map<string::iterator, string>& fp, string& p)

I get C2280 compiler's error. I need to store pointers to parts of string. I think that I need to convert iterator to pointer, but to which pointer?

Answer 1

The type std::string::iterator is implementation defined, so there might or might not be a specialisation of std::hash for it. If there isn't, then you need to write one. If there is, then you must not write one.

There definitely will be a specialisation for std::string::pointer , so you could use that instead, although you will have to be careful about iterator's that equal the string's end() .