std::span.size() vs array/vector size

Question

We are playing around with std::span() (using the gsl implementation for now) at work. Recently we discovered that comparing a std::span.size() to a vector.size() was giving a -Wsign-compare error :

if( span.size() > vector.size() ) // comparison between signed and unsigned integer expressions [-Wsign-compare]

I don't think we want to cast at every one of these comparisons. Our coding guidelines treat these warnings as errors. Curious if anyone has any ideas or suggestions?

Answer 1

您可以使用迭代器，并且都可以使用函数std::distance() 。

if (std::distance(s.begin(), s.end()) > std::distance(v.begin(), v.end()))