BOOST_FOREACH Macrosu

Giriş
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#include <boost/foreach.hpp>

Örnek
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BOOST_FOREACH(int i, v)
{
  std::cout << i << std::endl;
}

graph breadth_first_search metodu

Giriş
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#include <boost/graph/breadth_first_search.hpp>

Örnek
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class BreadthFirstSearchVisitor : public boost::default_bfs_visitor
{
  ...
};

GraphType g = ...;
BreadthFirstSearchVisitor breadthFirstSearchVisitor(g);

unsigned int startVertex = 0;

// named argument signature
breadth_first_search(g, vertex(startVertex, g),
 visitor(breadthFirstSearchVisitor).color_map(get(boost::vertex_color_t(), g)));

Örnek
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VertexDescr source = ...; 
VertexDescr target = ...;
DirectedGraph const  g = ...;

std::vector<double> distances(num_vertices(g));
std::vector<boost::default_color_type> colormap(num_vertices(g));

// Run BFS and record all distances from the source node
breadth_first_search(g, source,
  visitor(make_bfs_visitor(boost::record_distances(distances.data(),
    boost::on_tree_edge())))
    .color_map(colormap.data())
);

for (auto vd : boost::make_iterator_range(vertices(g)))
  if (colormap.at(vd) == boost::default_color_type{})
    distances.at(vd) = -1;




python exec metodu

Giriş
Açıklaması şöyle

Effects

Execute Python source code from code in the context specified by the dictionaries globals and locals.

Returns

An instance of object which holds the result of executing the code.

C++ içinde Python kodunu çalıştırır.

Örnek
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using namespace boost::python;

Py_Initialize();

object main_module = import("__main__");
object main_namespace = main_module.attr("__dict__");

try
{
  std::string comm = ...;

  object bar = exec(comm.c_str(), main_namespace);
  if (bar.is_none())
    std::cout << "None\n";
}
catch (error_already_set const &)
{
  PyErr_Print();
}

Örnek
Şöyle yaparız.

const char *prog = "def ack(m, n):\n"
                     "  if m == 0:\n"
                     "    return n + 1\n"
                     "  elif n == 0:\n"
                     "    return ack(m - 1, 1)\n"
                     "  else:\n"
                     "    return ack(m - 1, ack(m, n - 1))";

Py_Initialize();

boost::python::object mainModule = boost::python::import("__main__");
boost::python::object mainNamespace = mainModule.attr("__dict__");

boost::python::exec(prog, mainNamespace, mainNamespace);
int val = boost::python::extract<int>(
  boost::python::eval("ack(3,3)", mainNamespace, mainNamespace));