#include <string>
#include <cassert>
template <class S>
void
test(S s, typename S::difference_type pos, S expected)
{
typename S::const_iterator p = s.begin() + pos;
typename S::iterator i = s.erase(p);
assert(s.__invariants());
assert(s == expected);
assert(i - s.begin() == pos);
}
int main()
{
typedef std::string S;
test(S("abcde"), 0, S("bcde"));
test(S("abcde"), 1, S("acde"));
test(S("abcde"), 2, S("abde"));
test(S("abcde"), 4, S("abcd"));
test(S("abcdefghij"), 0, S("bcdefghij"));
test(S("abcdefghij"), 1, S("acdefghij"));
test(S("abcdefghij"), 5, S("abcdeghij"));
test(S("abcdefghij"), 9, S("abcdefghi"));
test(S("abcdefghijklmnopqrst"), 0, S("bcdefghijklmnopqrst"));
test(S("abcdefghijklmnopqrst"), 1, S("acdefghijklmnopqrst"));
test(S("abcdefghijklmnopqrst"), 10, S("abcdefghijlmnopqrst"));
test(S("abcdefghijklmnopqrst"), 19, S("abcdefghijklmnopqrs"));
}