定向非循环图形崩溃

Question

所以我的代码出现问题，无法确切地知道问题所在。我应该接受一个文本文件，其中第一行显示顶点数，第二行显示边数。从这个文本文件我试图获取显示的值然后构建一个图并确定是否或不包含一个循环。然后显示没有传入边的节点。 t1.txt

3
2
1,2,
2,3

我不确定我错在哪里。

t2.txt

5
5
3,4,
4,5,
2,3,
1,3,
3,5

//

#include <iostream>
#include <fstream>
#include <sstream>
#include<string>
#include<list>
#include <limits.h>
#include <stack>
#include<stdlib.h>
#include <cstdlib>



using namespace std;


class Graph
{
    int V;    // No. of vertices
    list<int> *adj;    // Pointer to an array containing adjacency lists
    bool isCyclicUtil(int v, bool visited[], bool *rs);  // used by isCyclic()
public:
    Graph(int V);   // Constructor
    void addEdge(int v, int w);   // to add an edge to graph
    bool isCyclic();    // returns true if there is a cycle in this graph
};

Graph::Graph(int V)
{
    this->V = V;
    adj = new list<int>[V];
}

void Graph::addEdge(int v, int w)
{
    adj[v].push_back(w); // Add w to v’s list.
}


bool Graph::isCyclicUtil(int v, bool visited[], bool *recStack)
{
    if(visited[v] == false)
    {
        // Mark the current node as visited and part of recursion stack
        visited[v] = true;
        recStack[v] = true;

        // Recur for all the vertices adjacent to this vertex
        list<int>::iterator i;
        for(i = adj[v].begin(); i != adj[v].end(); ++i)
        {
            if ( !visited[*i] && isCyclicUtil(*i, visited, recStack) )
                return true;
            else if (recStack[*i])
                return true;
        }

    }
    recStack[v] = false;  // remove the vertex from recursion stack
    return false;
}

// Returns true if the graph contains a cycle, else false.
bool Graph::isCyclic()
{
    // Mark all the vertices as not visited and not part of recursion
    // stack
    bool *visited = new bool[V];
    bool *recStack = new bool[V];
    for(int i = 0; i < V; i++)
    {
        visited[i] = false;
        recStack[i] = false;
    }

    // Call the recursive helper function to detect cycle in different
    // DFS trees
    for(int i = 0; i < V; i++)
        if (isCyclicUtil(i, visited, recStack))
            return true;

    return false;
}

int main()
{
    float n ,n2;

    string filename,line;
    cout << "Enter filename: ";
    cin >> filename;
    fstream file;
    file.open(filename.c_str());
    file >> n;
    file >> n2;
    int num = n;
    cout << num << " ";
    int num2 = n2;
    cout << num2 << " ";
    string matrix[num2][2];
    //int ** mat = new int*[num2];
    int mat[num2][2];
    Graph g(num);

    while(!file.eof())
   {
       for(int i = 0; i < num2; i++)
       {
          //mat[i] = new int[num];
           for(int j = 0; j < 2; j++)
           {
               if(getline(file,line,','))
               {
                   matrix[i][j] = line; // read file into string matrix
                  istringstream(line) >> mat[i][j]; //convert to int and store in dynamic 2d array
               }
           }
       }
   }
   cout << endl << "TEST " <<  mat[0][0] << " "  << mat[0][1] << " " << mat[1][0]<< " " << mat[1][1];
   for(int i = 0; i <num2-1; i++)
   {
        int temp1,temp2;
        temp1 = mat[i][0];
        temp2 = mat[i][1];
        g.addEdge(temp1,temp2);
   }
   if(g.isCyclic())//Here is where the program crashes for input t2.txt
        cout << "Graph is not DAG";
   else
        cout << "Graph is DAG";

    return 0;
}