void swap(basic_string& s) SPROUT_NOEXCEPT_EXPR(SPROUT_NOEXCEPT_EXPR(std::swap(std::declval<T&>(), std::declval<T&>())));
#include <sprout/string.hpp>
#include <sprout/assert.hpp>
using namespace sprout;
auto x = string<8>("homuhomu");
auto y = string<8>("madocchi");
int main() {
swap(x, y);
SPROUT_ASSERT_MSG(x == "madocchi" && y == "homuhomu", "each element are swapped.");
}