Boost C++ Libraries

libs/graph/example/grid_graph_example.cpp

//=======================================================================
// Copyright 2009 Trustees of Indiana University.
// Authors: Michael Hansen, Andrew Lumsdaine
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================

#include <iostream>
#include <boost/array.hpp>
#include <boost/graph/grid_graph.hpp>

#define DIMENSIONS 3
using namespace boost;

typedef grid_graph< DIMENSIONS > Graph;
typedef graph_traits< Graph > Traits;

// Define a simple function to print vertices
void print_vertex(Traits::vertex_descriptor vertex_to_print)
{
    std::cout << "(" << vertex_to_print[0] << ", " << vertex_to_print[1] << ", "
              << vertex_to_print[2] << ")" << std::endl;
}

int main(int argc, char* argv[])
{

    // Define a 3x5x7 grid_graph where the second dimension doesn't wrap
    boost::array< std::size_t, 3 > lengths = { { 3, 5, 7 } };
    boost::array< bool, 3 > wrapped = { { true, false, true } };
    Graph graph(lengths, wrapped);

    // Do a round-trip test of the vertex index functions
    for (Traits::vertices_size_type v_index = 0; v_index < num_vertices(graph);
         ++v_index)
    {

        // The two indicies should always be equal
        std::cout << "Index of vertex " << v_index << " is "
                  << get(boost::vertex_index, graph, vertex(v_index, graph))
                  << std::endl;
    }

    // Do a round-trip test of the edge index functions
    for (Traits::edges_size_type e_index = 0; e_index < num_edges(graph);
         ++e_index)
    {

        // The two indicies should always be equal
        std::cout << "Index of edge " << e_index << " is "
                  << get(boost::edge_index, graph, edge_at(e_index, graph))
                  << std::endl;
    }

    // Print number of dimensions
    std::cout << graph.dimensions() << std::endl; // prints "3"

    // Print dimension lengths (same order as in the lengths array)
    std::cout << graph.length(0) << "x" << graph.length(1) << "x"
              << graph.length(2) << std::endl; // prints "3x5x7"

    // Print dimension wrapping (W = wrapped, U = unwrapped)
    std::cout << (graph.wrapped(0) ? "W" : "U") << ", "
              << (graph.wrapped(1) ? "W" : "U") << ", "
              << (graph.wrapped(2) ? "W" : "U")
              << std::endl; // prints "W, U, W"

    // Start with the first vertex in the graph
    Traits::vertex_descriptor first_vertex = vertex(0, graph);
    print_vertex(first_vertex); // prints "(0, 0, 0)"

    // Print the next vertex in dimension 0
    print_vertex(graph.next(first_vertex, 0)); // prints "(1, 0, 0)"

    // Print the next vertex in dimension 1
    print_vertex(graph.next(first_vertex, 1)); // prints "(0, 1, 0)"

    // Print the 5th next vertex in dimension 2
    print_vertex(graph.next(first_vertex, 2, 5)); // prints "(0, 0, 4)"

    // Print the previous vertex in dimension 0 (wraps)
    print_vertex(graph.previous(first_vertex, 0)); // prints "(2, 0, 0)"

    // Print the previous vertex in dimension 1 (doesn't wrap, so it's the same)
    print_vertex(graph.previous(first_vertex, 1)); // prints "(0, 0, 0)"

    // Print the 20th previous vertex in dimension 2 (wraps around twice)
    print_vertex(graph.previous(first_vertex, 2, 20)); // prints "(0, 0, ?)"
}