I've written my own code to parse an .obj model file - essentially just ASCII text. The file gets parsed and stored in the class correctly according to my tests. I can read back the values (from data members) just fine in the loading function.

The problem occurs when I try to read back the values in my main rendering loop. There is an access violation error on the line beginning "int v":

```
 for(int i = 0; i<data.numFaces; i++){
  for(int j = 0; j<3; j++){ //Assuming triangles for now.

   int v = data.faceList[i].vertex[j]; // Access violation here.
   double vX = data.vertexList[v].x;
   double vY = data.vertexList[v].y;
   double vZ = data.vertexList[v].z;
   glVertex3d(vX, vY, vZ);
  }
 }

```

I'm not exactly sure why this happens, and I've checked everything I could possibly think of. I'm not very experienced in C++. Most of my programming experience is in Java, Python and PHP although I have previously written a medium sized project in C++.

I'm sure the problem is something basic related to memory allocation or pointers used for the dynamic arrays.

Here are the relevant parts of code in the obj loading class:

```
ObjData ObjLoader::LoadObj(std::string filename){

    //... Initalization ...

 // 1st pass: find number of elements so array sizes can be defined.
 while(!file.eof()){
  //...
 }

 //...close file...

 _data.faceList = new ObjFace[_data.numFaces];
 _data.vertexList = new ObjVert[_data.numVertices];
 _data.uvList = new ObjUV[_data.numUVcoords];
 _data.normalList = new ObjNormal[_data.numNormals];

    //TODO: Make size dynamic according to each face. Just use the first 3 points for now.
 for (int i = 0; i < _data.numFaces; i++){
  _data.faceList[i].vertex = new int[3];
  _data.faceList[i].normal = new int[3];
  _data.faceList[i].uv = new int[3];
 }

 //... file stuff ...

 // 2nd pass: read values into arrays.
 while(!file.eof()){
  //...

  if(type=="v"){
   _data.vertexList[currentVertex].x = atof(param1.c_str());
   _data.vertexList[currentVertex].y = atof(param2.c_str());
   _data.vertexList[currentVertex].z = atof(param3.c_str());
   currentVertex++;
  }else if(type=="vt"){
   _data.uvList[currentUV].u = atof(param1.c_str());
   _data.uvList[currentUV].v = atof(param2.c_str());
   currentUV++;
  }else if(type=="vn"){
   _data.normalList[currentNormal].x = atof(param1.c_str());
   _data.normalList[currentNormal].y = atof(param2.c_str());
   _data.normalList[currentNormal].z = atof(param3.c_str());
   currentNormal++;
  }else if(type=="f"){
  //...Within loop over each vertex in a single face ...

        if(endPos != string::npos){
        // Value before 1st "/" (Vertex index).
        // ...find value in string...
        _data.faceList[currentFace].vertex[i] = atoi(token.c_str()) -1; // File format begins indices from 1.

        // Value between slashes (UV index).
        // ...find value in string...
        _data.faceList[currentFace].uv[i] = atoi(token.c_str()) -1;

        // Value after 2nd "/" (Normal index).
        // ...find value in string...
        _data.faceList[currentFace].normal[i] = atoi(token.c_str()) -1;
   }
//...End of loop over every vertex in a single face...
currentFace++;
}

}

 return _data;

    }

```

And the structs ObjFace, ObjVert, ObjUV and ObjNormal are defined as:

```
    struct ObjVert{
       float x, y, z;
    };

    struct ObjUV{
      float u, v;
    };

    struct ObjNormal{
       float x, y, z;
    };

    // Contains indexes.
       struct ObjFace{
       int* vertex;
       int* uv;
       int* normal;
    };

```

Thanks for any help. Also, any good sources on avoiding these types of errors in future would be appreciated.