c++ - add value from file to double pointer -

my .h file

#ifndef adjacencymatrix_h_ #define adjacencymatrix_h_ #include <iostream> #include <fstream> #include <cstring> #include <cstdio> #include <cstdlib> using namespace std;    class adjacencymatrix{  private:     int vertexcount;     int vertexfirst;     int edgecount;     int **wage;     int **matrix;  public:     adjacencymatrix();     virtual ~adjacencymatrix();     bool createfromfile(string path);     void viewmatrix();    };  #endif /* adjacencymatrix_h_ */ 

i read form file , want write initialized matrix, doesn’t work. can me ?

#include "adjacencymatrix.h"  adjacencymatrix::adjacencymatrix() {     this->vertexcount=0;     this->vertexfirst=-1;     this->edgecount=0;        }  adjacencymatrix::~adjacencymatrix() { }  bool adjacencymatrix::createfromfile(string path) {     fstream file;     file.open(path.c_str(), fstream::in);     if (file.good())     {         int vertexf,vertexe,wag;         cout << "file opened" << endl;         file >> this->edgecount;         file >> this->vertexcount;         file >> this->vertexfirst;          matrix = new int *[edgecount];         wage = new int *[edgecount];          (int = 0; < vertexcount; i++)         {             matrix[i]=new int[edgecount];             wage[i]=new int[edgecount];         }          //fill matrix zeros         (int = 0; < vertexcount; i++)         {              for(int j=0; j<edgecount;j++)             {                 matrix[i][j]=0;                 wage[i][j]=0;             }         }          // fill matrix 1         for(int i=0; i<edgecount; i++)         {             file >> vertexf >> vertexe >> wag;             cout << " w " << wag;             matrix[vertexf][vertexe] = 1;         }          file.close();         return true;     }     cout << "file not opened" << endl;     return false; }  void adjacencymatrix::viewmatrix(){     cout << " adjacency matrix ";     for(int i=0; i<vertexcount; i++)     {             for(int j=0; i<edgecount;i++) {                   cout << this->matrix[i][j] << " ";             }             cout<< endl;     } } 

and part not work(i mean, nothing display , showmatrix() not work). want value file , write matrix[x][y] = 1 because want create graph path.

for(int i=0; i<edgecount; i++) {     file >> vertexf >> vertexe >> wag; // cout work in line      matrix[vertexf][vertexe] = 1; // not work  } 

the size of matrix wrong:

matrix = new int *[edgecount]; // wrong size wage = new int *[edgecount];   // wrong size  (int = 0; < vertexcount; i++)     {         matrix[i]=new int[edgecount];         wage[i]=new int[edgecount];     } 

when define matrix should use vertexcount instead, this:

matrix = new int *[vertexcount]; wage   = new int *[vertexcount]; 

this might lead segmentation faults or strange behaviour.

also, when read data provided user should validate them:

file >> vertexf >> vertexe >> wag; matrix[vertexf][vertexe] = 1; 

are sure vertexf , vertexe aren't larger vertexcount - 1 , edgecount - 1?