C++图形构建问题

你好，我想构建一个连接句子的图。例如，我的文件有以下几行。

ab cd ef
ef gh ij
ij kl mn
xy ab cd

所以我希望每个节点都应该有一条线，即ab cd ef应该是一个节点，它应该连接到ef gh ij，而CCD_2应该连接到CCD _3。

基本上，一行的最后一个字应该连接到第一个字和最后一个词匹配的任何一行。

以下是我迄今为止提出的内容，但在添加Edges时失败了。

#include <map>
#include <string>
#include <deque>
#include <list>
#include <iostream>
#include <stack>
#include <fstream>
#include <vector>
class GraphNode {
public:
    GraphNode(std::string name) {
        std::vector<std::string> words;
        std::string::size_type lastPos = name.find_first_not_of(' ', 0);
        std::string::size_type pos     = name.find_first_of(' ', lastPos);
        while (std::string::npos != pos || std::string::npos != lastPos){
            words.push_back(name.substr(lastPos, pos - lastPos));
            lastPos = name.find_first_not_of(' ', pos);
            pos = name.find_first_of(' ', lastPos);
        }
        first = words[0];
        middle = " ";
        for ( int i = 1; i < (int)words.size() - 1; i++) {
            middle = words[i] + " ";
        }
        last = words[words.size() - 1 ];
    }
    ~GraphNode() {};
    std::string first;
    std::string middle;
    std::string last;
};
struct GraphNodeCompare {
   bool operator() (const GraphNode& lhs, const GraphNode& rhs) {
       return lhs.last < rhs.last;
   }
};
class Graph {
public:
    Graph() {}
    ~Graph() {}
    typedef std::map <GraphNode, std::list<GraphNode>, GraphNodeCompare > GraphType;
    void AddVertex  ( GraphNode vertexID );
    void AddEdge    ( GraphNode vertexLeft, GraphNode vertexRight);
    std::list<GraphNode> GetVertices(GraphNode vertexID);   
    friend std::ostream& operator << (std::ostream& os, const Graph& dt);
private:
    GraphType m_graph;
protected:
};
void Graph::AddVertex(GraphNode vertexID) {
    GraphType::const_iterator iter = m_graph.find(vertexID);
    if ( iter == m_graph.end()) {
        std::list<GraphNode> list;
        m_graph[vertexID] = list;
    }
}
void Graph::AddEdge( GraphNode vertexLeft, GraphNode vertexRight) {
    AddVertex(vertexLeft);
    AddVertex(vertexRight);
    m_graph[vertexLeft].push_back(vertexRight);
    m_graph[vertexRight].push_back(vertexLeft);
}
std::list<GraphNode> Graph::GetVertices(GraphNode vertexID) {
    GraphType::const_iterator iter = m_graph.find(vertexID);
    std::list<GraphNode> list;
    if ( iter != m_graph.end()){
        return m_graph[vertexID];
    }
    return list;
}
std::ostream& operator << (std::ostream& os, const Graph& graph) {
    std::cout << "---------------------------------------------" << std::endl;
    std::map<GraphNode, std::list<GraphNode>, GraphNodeCompare >::const_iterator iter;
    for ( iter = graph.m_graph.begin(); iter != graph.m_graph.end(); ++iter) {
        std::cout << iter->first.first << iter->first.middle << iter->first.last << " : " ;
        std::list<GraphNode> list = iter->second;
        std::list<GraphNode>::const_iterator iter1;
        for ( iter1 = list.begin(); iter1 != list.end(); ++iter1) {
            std::cout << iter1->first << iter1->middle << iter1->last << 't' ;
        }
        std::cout << std::endl;
    }
    std::cout << "---------------------------------------------" << std::endl;
    return os;
}
int main( int argc, char **argv) {
    Graph *pGraph = new Graph();
    std::ifstream dataFile("D:\personal\data\datas3.txt");
    if ( dataFile.peek() == EOF ) {
        return -1;
    }    
    if (dataFile.is_open()) {
        while (! dataFile.eof() ) {
            std::string line;
            std::getline (dataFile,line);
            GraphNode node(line);
            pGraph->AddVertex(node);
            std::list<GraphNode> vertices = pGraph->GetVertices(node);
            for ( std::list<GraphNode>::iterator itr = vertices.begin(); itr != vertices.end(); ++itr) {
                pGraph->AddEdge( node, *itr);
            }
            //std::cout << line << std::endl;
        }
    }
    dataFile.close();
    //std::cout << *pGraph;
    delete pGraph;
}