#include <regex>
#include <cassert>
void
test()
{
std::match_results<const char*> m;
const char s[] = "abcdefghijk";
assert(std::regex_search(s, m, std::regex("cd((e)fg)hi")));
assert(m.position() == std::distance(s, m[0].first));
assert(m.position(0) == std::distance(s, m[0].first));
assert(m.position(1) == std::distance(s, m[1].first));
assert(m.position(2) == std::distance(s, m[2].first));
assert(m.position(3) == std::distance(s, m[3].first));
assert(m.position(4) == std::distance(s, m[4].first));
}
int main()
{
test();
}