Question

构建一个增强图，其中边缘区域添加（下方），v1定义为

gm->create_edge(v1,v2,1); 
boost::graph_traits<Graph>::vertex_descriptor v1 = gm-> create_vertex("one",1,1);

如何使用？：

打印或枚举顶点

boost::graph_traits<Graph>::vertex_descriptor vd;

这允许我打印顶点id：

Graph::vertex_iterator v, vend, vnext; 
for (boost::tie(v, vend) = vertices(gm->g); v != vend; ++v)
    std::cout << gm->g[*v].id << ", "  << gm->g[*v].color << ", ";

我有一个节点程度的函数，它需要一个顶点描述符，所以，我该如何传递它？

gm->degree( takes vertex_descriptor )?

此links已结束。

Answer 1

vertices(g)返回一个迭代器对。指向迭代器会给出描述符。在您自己的示例中，v为vertex_iterator，因此*v为vertex_descriptor。

让我们使用Boost的degree函数 - 它也需要一个描述符：

<强> Live On Coliru

#include <boost/graph/adjacency_list.hpp>

namespace MyProgram {
    using namespace boost;
    struct VertexProps { int id; default_color_type color; };

    using Graph = adjacency_list<vecS, vecS, directedS, VertexProps>;

    Graph make_sample_graph();
}

#include <iostream>

int main() {
    using MyProgram::Graph;
    Graph g = MyProgram::make_sample_graph();

    Graph::vertex_iterator v, vend;
    for (boost::tie(v, vend) = vertices(g); v != vend; ++v) {
        std::cout << "Vertex descriptor #" << *v 
             << " degree:" << degree(*v, g)
             << " id:"     << g[*v].id
             << " color:"  << g[*v].color
             << "\n";
    }
}

我更喜欢使用ranged-for：

<强> Live On Coliru

for (auto vd : boost::make_iterator_range(vertices(g))) {
    std::cout << "Vertex descriptor #" << vd 
         << " degree:" << degree(vd, g)
         << " id:"     << g[vd].id
         << " color:"  << g[vd].color
         << "\n";
}

为了完整性make_sample_graph()：

namespace MyProgram {
    Graph make_sample_graph() {
        Graph g(10);
        for (auto vd : boost::make_iterator_range(vertices(g)))
            g[vd] = { int(vd)*100, {} };

        add_edge(1,2,g);
        add_edge(2,3,g);
        add_edge(4,5,g);
        add_edge(4,6,g);
        add_edge(6,7,g);

        return g;
    }
}

打印：

Vertex descriptor #0 degree:0 id:0 color:0
Vertex descriptor #1 degree:1 id:100 color:0
Vertex descriptor #2 degree:2 id:200 color:0
Vertex descriptor #3 degree:1 id:300 color:0
Vertex descriptor #4 degree:2 id:400 color:0
Vertex descriptor #5 degree:1 id:500 color:0
Vertex descriptor #6 degree:2 id:600 color:0
Vertex descriptor #7 degree:1 id:700 color:0
Vertex descriptor #8 degree:0 id:800 color:0
Vertex descriptor #9 degree:0 id:900 color:0

使用vertex_descriptor boost图打印或迭代顶点

1 个答案: