text: //===----------------------------------------------------------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is dual licensed under the MIT and the University of Illinois Open
  // Source Licenses. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  
  // <string>
  
  // size_type rfind(charT c, size_type pos = npos) const;
  
  #include <string>
  #include <cassert>
  
  template <class S>
  void
  test(const S& s, typename S::value_type c, typename S::size_type pos,
       typename S::size_type x)
  {
      assert(s.rfind(c, pos) == x);
      if (x != S::npos)
          assert(x <= pos && x + 1 <= s.size());
  }
  
  template <class S>
  void
  test(const S& s, typename S::value_type c, typename S::size_type x)
  {
      assert(s.rfind(c) == x);
      if (x != S::npos)
          assert(x + 1 <= s.size());
  }
  
  typedef std::string S;
  
  int main()
  {
      test(S(""), 'b', 0, S::npos);
      test(S(""), 'b', 1, S::npos);
      test(S("abcde"), 'b', 0, S::npos);
      test(S("abcde"), 'b', 1, 1);
      test(S("abcde"), 'b', 2, 1);
      test(S("abcde"), 'b', 4, 1);
      test(S("abcde"), 'b', 5, 1);
      test(S("abcde"), 'b', 6, 1);
      test(S("abcdeabcde"), 'b', 0, S::npos);
      test(S("abcdeabcde"), 'b', 1, 1);
      test(S("abcdeabcde"), 'b', 5, 1);
      test(S("abcdeabcde"), 'b', 9, 6);
      test(S("abcdeabcde"), 'b', 10, 6);
      test(S("abcdeabcde"), 'b', 11, 6);
      test(S("abcdeabcdeabcdeabcde"), 'b', 0, S::npos);
      test(S("abcdeabcdeabcdeabcde"), 'b', 1, 1);
      test(S("abcdeabcdeabcdeabcde"), 'b', 10, 6);
      test(S("abcdeabcdeabcdeabcde"), 'b', 19, 16);
      test(S("abcdeabcdeabcdeabcde"), 'b', 20, 16);
      test(S("abcdeabcdeabcdeabcde"), 'b', 21, 16);
  
      test(S(""), 'b', S::npos);
      test(S("abcde"), 'b', 1);
      test(S("abcdeabcde"), 'b', 6);
      test(S("abcdeabcdeabcdeabcde"), 'b', 16);
  }
  