Question

此错误的原因是什么？我无法弄清楚它来自哪里。代码编译并运行，但在它说文件加载后，它就吓坏了。在调试器中运行它没有任何好处，它没有发现任何错误。

#include <iostream>
#include <fstream>
#include <map>
#include <vector>
#include <string>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/visitors.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/graph/dijkstra_shortest_paths.hpp>
#include <boost/graph/metis.hpp>

using namespace std;
using namespace boost;

typedef adjacency_list_traits<
vecS, vecS, undirectedS, listS> GraphTraits;
// type 'Vertex' identifies each vertex uniquely:
typedef GraphTraits::vertex_descriptor Vertex;
// Property type associated to each vertex:
struct VertexProperty {
string name;  // Name of vertex (i.e., "location")
Vertex predecessor; // Predecessor along optimal path.
double distance; // Distance to the goal, along shortest path.
default_color_type color; // for use by dijkstra.
VertexProperty(const string& aName = "") : name(aName) { };
};
// Property type associated to each edge:
struct EdgeProperty {
double weight; // distance to travel along this edge.
EdgeProperty(double aWeight = 0.0) : weight(aWeight) { };
};
// Type of the graph used:
typedef adjacency_list<
vecS, // out-edges stored in vector 
vecS, // vertices stored in vector
undirectedS, // undirected graph (edge don't have a specific direction)
VertexProperty, // properties associated to each vertex.
EdgeProperty // properties associated to each edge.
> Graph;
// Create a global graph object 'g'
Graph g;
// This is a visitor for the dijkstra algorithm. This visitor does nothing special.
struct do_nothing_dijkstra_visitor {
template <typename Vertex, typename Graph>
void initialize_vertex(Vertex u, const Graph& g) const { };
template <typename Vertex, typename Graph>
void examine_vertex(Vertex u, const Graph& g) const { };
template <typename Edge, typename Graph>
void examine_edge(Edge e, const Graph& g) const { };
template <typename Vertex, typename Graph>
void discover_vertex(Vertex u, const Graph& g) const { };
template <typename Edge, typename Graph>
void edge_relaxed(Edge e, const Graph& g) const { };
template <typename Edge, typename Graph>
void edge_not_relaxed(Edge e, const Graph& g) const { };
template <typename Vertex, typename Graph>
void finish_vertex(Vertex u, const Graph& g) const { };
};
int main() {
string tempName1;
string tempName2;
string tempString;
string data2;
double weight;
cout << "please enter the data file name: ";
char strFileName[256];
cin >> strFileName;
// preparing the data
ifstream fin;
fin.open(strFileName);
if (!fin) {
    cerr << "Can't open data file, leaving...\n";
    return EXIT_FAILURE;
}
else{
    cout << "file loaded." << endl << endl;
}
// Create a map to associate names to vertices of the graph:
map<string, Vertex> name2v;
getline(fin, tempString); //Vertices:
getline(fin, tempString); //Location1, Location2, ...
stringstream tempSS(tempString);
while (getline(tempSS, tempName1, ',')) {
    // Add vertex to graph, with name 'tempName1' and 
    //  record the associated Vertex in the name2v map:
    name2v[tempName1] = add_vertex(VertexProperty(tempName1), g);
}
getline(fin, tempString); //Edges:
while (getline(fin, tempString)){ // (Location1, Location2, 6)
    //remove parentheses
    tempString.erase(tempString.begin(), tempString.begin() +  
 tempString.find('(') + 1);
    tempString.erase(tempString.begin() + tempString.find(')'), 
 tempString.end());
    stringstream temp_ss(tempString);
    getline(temp_ss, tempName1, ',');
    getline(temp_ss, tempName2, ',');
    temp_ss >> weight;
    // Add edge to graph, by finding vertices associated 
    //  to tempName1 and tempName2:
    add_edge(name2v[tempName1], name2v[tempName2], EdgeProperty(weight), g);
}
char x;
Vertex current_vertex;
Vertex start_vertex;
Vertex goal_vertex;
cout << endl << "How would you like to process your data file?" << endl;
cout << "1.) shortest path" << endl;
cout << "2.) minimum spanning tree" << endl;
cout << "3.) Travelling Salesman" << endl << endl;
returnQuestion:
cout << "please enter 1,2,3 or Q to quit: ";
cin >> x;
switch (x){
case '1': //do the work for shortest path
    cout << endl << "please enter the location name to start from: ";
    cin >> tempName1;
    cout << endl << "please enter the location name for the destination: ";
    cin >> tempName2;
    // Retrieve the vertices for the start and goal:
    start_vertex = name2v[tempName1];
    goal_vertex = name2v[tempName2];
    cout << g[name2v[tempName1]].name << g[name2v[tempName2]].name;
    dijkstra_shortest_paths(
        g, goal_vertex, //<-- solve to goal 
        get(&VertexProperty::predecessor, g),
        get(&VertexProperty::distance, g),
        get(&EdgeProperty::weight, g),
        identity_property_map(), // index-map
        less<double>(), // compare
        plus<double>(), // combine 
        numeric_limits<double>::infinity(), // infinity
        0.0, // zero
        do_nothing_dijkstra_visitor(),
        get(&VertexProperty::color, g));
    cout << "distances and parents:" << endl;
    // Traverse the vertices from the start to goal,
    //  through the "predecessor" links:
    current_vertex = start_vertex;
    while (current_vertex != goal_vertex) {
        cout << g[current_vertex].name << " " << 
 g[current_vertex].distance;
        current_vertex = g[current_vertex].predecessor;
    };
    cout << g[goal_vertex].name << " " << g[goal_vertex].distance << endl;
    break;
case '2': //do the work for minimum spanning
    break;
case '3': //do the work for travelling salesman
    break;
case 'q':
case 'Q':
    return EXIT_SUCCESS;
    break;
default:
    goto returnQuestion;
}
system("pause");
}

Answer 1

检查文件中是否有空行。如果边缘填充循环找到一个空行，它会给你准确的错误，因为你试图在不存在的位置擦除字符。

string iterator + offset超出范围

1 个答案: