Tell `string::operator==` to start comparing at the back of the string

Question

Is it possible/(relatively) easy/std™ to start comparing at the back of a string or should I write my own function for that? It would be relatively straightforward of course, but still, I would trust a standard library implementation over mine any day.

The end of the string is almost unique, and the front is quite common, that's the only reason I need this "optimization".

Thanks!

Answer 1

Best I can think of so far is str1.size() == str2.size() && std::equal(str1.rbegin(), str1.rend(), str2.rbegin())

Answer 2

You could use std::equal in combination with std::basic_string::reverse_iterator (rbegin, rend).

However, it is relevant only if the strings have the same lenght (so you need first to check the sizes) and only for equality of the strings (since the most significant difference will be the last compared while iterating).

Example:

bool isEqual = s1.size() == s2.size() && std::equal( s1.rbegin(), s1.rend(), s2.rbegin());