factorial_seq.cpp 1.4 KB

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  1. // Copyright (C) 2009-2012 Lorenzo Caminiti
  2. // Distributed under the Boost Software License, Version 1.0
  3. // (see accompanying file LICENSE_1_0.txt or a copy at
  4. // http://www.boost.org/LICENSE_1_0.txt)
  5. // Home at http://www.boost.org/libs/local_function
  6. #include <boost/local_function.hpp>
  7. #include <boost/typeof/typeof.hpp>
  8. #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
  9. #include <boost/detail/lightweight_test.hpp>
  10. #include <algorithm>
  11. #include <vector>
  12. struct calculator;
  13. BOOST_TYPEOF_REGISTER_TYPE(calculator) // Register before `bind this_` below.
  14. struct calculator {
  15. std::vector<int> results;
  16. void factorials(const std::vector<int>& nums) {
  17. int BOOST_LOCAL_FUNCTION( (bind this_) (int num)
  18. (bool recursion)(default false) ) {
  19. int result = 0;
  20. if(num <= 0) result = 1;
  21. else result = num * factorial(num - 1, true);
  22. if(!recursion) this_->results.push_back(result);
  23. return result;
  24. } BOOST_LOCAL_FUNCTION_NAME(recursive factorial)
  25. std::for_each(nums.begin(), nums.end(), factorial);
  26. }
  27. };
  28. int main(void) {
  29. std::vector<int> v(3);
  30. v[0] = 1; v[1] = 3; v[2] = 4;
  31. calculator calc;
  32. calc.factorials(v);
  33. BOOST_TEST(calc.results[0] == 1);
  34. BOOST_TEST(calc.results[1] == 6);
  35. BOOST_TEST(calc.results[2] == 24);
  36. return boost::report_errors();
  37. }