Boost圖形轉換錯誤

Question

我正在使用boost庫創建一個簡單的圖，並嘗試遍歷頂點和邊緣。 但是我收到以下錯誤，其中代碼可以遍歷所有頂點，但是當我添加負責遍歷邊緣的最后一段代碼時，存在編譯問題：

錯誤：從'std :: pair，boost :: detail :: out_edge_iter>轉換，long unsigned int，boost :: detail :: edge_desc_impl，long int>，boost :: adjacency_list>，boost :: detail :: adj_list_edge_iterator，boost :: detail :: out_edge_iter>，長無符號整數，boost :: detail :: edge_desc_impl，long int>，boost :: adjacency_list>>到非標量類型'std :: pair，boost :: detail :: out_edge_iter < __gnu_cxx :: __ normal_iterator *，std :: vector，std :: allocator>>>，long unsigned int，boost :: detail :: edge_desc_impl，long int>，boost :: adjacency_list <>>，boost :: detail :: adj_list_edge_iterator ，boost :: detail :: out_edge_iter <__ gnu_cxx :: __ normal_iterator *，std :: vector，std :: allocator>>>，long unsigned int，boost :: detail :: edge_desc_impl，long int>，boost :: adjacency_list <> >>'請求boost :: adjacency_list <> :: edge_iterator> es = boost :: edges（g）;

這是我的代碼

#include <iostream>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>
int main()
{
    using namespace std;
    using namespace boost;

   typedef adjacency_list< listS, vecS, directedS > digraph;

   // instantiate a digraph object with 8 vertices
   digraph g(8);

   // add some edges
   add_edge(0, 1, g);
   add_edge(1, 5, g);
   add_edge(5, 6, g);
   add_edge(2, 3, g);
   add_edge(2, 4, g);
   add_edge(3, 5, g);
   add_edge(4, 5, g);
   add_edge(5, 7, g);

   // represent graph in DOT format and send to cout
   write_graphviz(cout, g);


   std::cout<< "+++++++++++++++++++++++++++++++++++++\n";
   std::cout<<"Print Vertices\n";

   std::pair<boost::adjacency_list<>::vertex_iterator,
      boost::adjacency_list<>::vertex_iterator> vs = boost::vertices(g);

    std::copy(vs.first, vs.second,std::ostream_iterator<boost::adjacency_list<>::vertex_descriptor>{
        std::cout, "\n"});


    std::cout<< "+++++++++++++++++++++++++++++++++++++\n";
    std::cout<<"Print Edges\n";

    std::pair<boost::adjacency_list<>::edge_iterator,
        boost::adjacency_list<>::edge_iterator> es = boost::edges(g);

      std::copy(es.first, es.second,std::ostream_iterator<boost::adjacency_list<>::edge_descriptor>{
          std::cout, "\n"});

   return 0;
}

Answer 1

您正在將edges的結果分配給不兼容類型的變量。 代替

std::pair<boost::adjacency_list<>::edge_iterator,
    boost::adjacency_list<>::edge_iterator> es = boost::edges(g);

采用

auto es = boost::edges(g);

要么

std::pair<digraph::edge_iterator, digraph::edge_iterator> es = boost::edges(g);

---

更多詳細信息：您的digraph類型為adjacency_list指定了三個模板參數：

typedef adjacency_list< listS, vecS, directedS > digraph;

可以使用這種類型的參數調用edges ，但是您必須指定函數的EdgeIterator模板參數必須為boost::adjacency_list<>::edge_iterator ，就像g屬於adjacency_list<>而不是adjacency_list<listS, vecS, directedS> 。 顯然，該轉換對adjacency_list<>::vertex_iterator有效，但對adjacency_list<>::edge_iterator 。