ceph/src/boost/libs/local_function/test/factorial.cpp

   1
   2 // Copyright (C) 2009-2012 Lorenzo Caminiti
   3 // Distributed under the Boost Software License, Version 1.0
   4 // (see accompanying file LICENSE_1_0.txt or a copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 // Home at http://www.boost.org/libs/local_function
   7
   8 #include <boost/config.hpp>
   9 #ifdef BOOST_NO_CXX11_VARIADIC_MACROS
  10 #   error "variadic macros required"
  11 #else
  12
  13 #include <boost/local_function.hpp>
  14 #include <boost/typeof/typeof.hpp>
  15 #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
  16 #include <boost/detail/lightweight_test.hpp>
  17 #include <algorithm>
  18 #include <vector>
  19
  20 struct calculator;
  21 BOOST_TYPEOF_REGISTER_TYPE(calculator) // Register before `bind this_` below.
  22
  23 //[factorial
  24 struct calculator {
  25     std::vector<int> results;
  26
  27     void factorials(const std::vector<int>& nums) {
  28         int BOOST_LOCAL_FUNCTION(bind this_, int num,
  29                 bool recursion, default false) {
  30             int result = 0;
  31
  32             if(num <= 0) result = 1;
  33             else result = num * factorial(num - 1, true); // Recursive call.
  34
  35             if(!recursion) this_->results.push_back(result);
  36             return result;
  37         } BOOST_LOCAL_FUNCTION_NAME(recursive factorial) // Recursive.
  38
  39         std::for_each(nums.begin(), nums.end(), factorial);
  40     }
  41 };
  42 //]
  43
  44 int main(void) {
  45     std::vector<int> v(3);
  46     v[0] = 1; v[1] = 3; v[2] = 4;
  47
  48     calculator calc;
  49     calc.factorials(v);
  50     BOOST_TEST(calc.results[0] == 1);
  51     BOOST_TEST(calc.results[1] == 6);
  52     BOOST_TEST(calc.results[2] == 24);
  53     return boost::report_errors();
  54 }
  55
  56 #endif // VARIADIC_MACROS
  57