Error invalid new expression of abstract class type

I am currently writing a raytracer for a university class.
In order to load Scenes from files I wrote an sdfloader to read sdf files and create scenes therefor.

if I now want to compile the loader i get the following error:

rc/sdf_loader.cpp: In member function 'void SDFloader::add_shape(std::istringstream&)':
src/sdf_loader.cpp:95:58: error: invalid new-expression of abstract class type 'box'
                                &scene_.materials[mat]));
                                                      ^

I tried to find a solution but failed.

The sdf_loader class looks like the following:

class SDFloader {
  public:
    SDFloader();
    ~SDFloader();

    Scene const& scene() const;
    void read(std::string file);

  private:
    void add_material(std::istringstream&);
    void add_shape(std::istringstream&);
    void add_light(std::istringstream&);
    void add_camera(std::istringstream&);
    void apply_transformation(std::istringstream&);

  private:
    Scene scene_;
};

in my implementation of the sdf loader i wrote the method read():

void SDFloader::add_shape(std::istringstream& iss) {

    std::string name;
    iss >> name;

    if(name == "box") {
      double x1,y1,z1,x2,y2,z2;
      std::string mat;
      iss >> name >> x1 >> y1 >> z1 >> x2 >> y2 >> z2 >> mat;
      scene_.shapes.insert(new box(point(x1,y1,z1),
                                   point(x2,y2,z2),
                                   name,
                                   &scene_.materials[mat]));
    }

and for every other shape the same calls.

Where is the Problem in my code? I really don’t see it

I am using g++-4.9 - std=c++0x to compile and link everything

#ifndef SORT_H_
#define SORT_H_

class Sort {
protected:
   unsigned long num_cmps; // number of comparisons performed in sort function
public:
   virtual void sort(int A[], int size)= 0;    // main entry point
   bool testIfSorted(int A[], int size);        // returns false if not sorted
                                            // true otherwise
   unsigned long getNumCmps() { return num_cmps; }        // returns # of comparisons
   void resetNumCmps() { num_cmps = 0; }
};

class MergeSort:public Sort {       // MergeSort class
public:
  void sort(int A[], int size, int low, int high);      // main entry point
};

#endif

Sort.cpp

 Sort* s;
   switch(op.getAlg()) 
      {
      case 'S':
         s=new SelectionSort();
         break;
      case 'I':
         s=new InsertionSort();
         break;
      case 'B':
         s=new BubbleSort();
         break;
      case 'H':
         s=new HeapSort();
         break;
      case 'R':
         s=new RadixSort();
         radixsortQ = true;
         break;
      case 'M':
         s=new MergeSort(); --> error
         break;
      }

Merge Sort.cpp

#include <iostream>
#include "Sort.h"
using namespace std;
void MergeSort::sort(int A[], int size, int low, int high)          // main entry point
{
    if (low < high){
        int middle = (low + high) / 2;
        MergeSort(A, size, low, middle);
        MergeSort(A, size, middle+1, high);
        merge(A, size, low, middle, high);
    }
}

void merge::sort(int A[], int size, int low, int middle, int high){
    int temp[size];
    for(int i = low; i <= high; i++){
        temp[i] = A[i];
    }
    int i = low;
    int j = middle + 1;
    int k = low;

    while(i <= middle && j <= high){
        if(temp[i] <= temp[j]){
            A[k] = temp[i];
            ++i;
        }
        else {
            A[k] = temp[j];
            ++j;
        }
        ++k;
    }
    while(i <= middle){
        A[k] = temp[i];
        ++k;
        ++i;
    }
}

There are always have a problem that list as follows :

———————————————-separating line —————————————————————
/home/qie/softs/ros_slam/Pangolin/src/video/drivers/openni2.cpp: In member function ‘virtual std::unique_ptrpangolin::VideoInterface pangolin::RegisterOpenNi2VideoFactory()::OpenNI2VideoFactory::Open(const pangolin::Uri&)’:
/home/qie/softs/ros_slam/Pangolin/src/video/drivers/openni2.cpp:656:71: error: invalid new-expression of abstract class type ‘pangolin::OpenNi2Video’
nivid = new OpenNi2Video(pangolin::PathExpand(uri.url));

/home/qie/softs/ros_slam/Pangolin/src/video/drivers/openni2.cpp:658:54: error: invalid new-expression of abstract class type ‘pangolin::OpenNi2Video’
nivid = new OpenNi2Video(stream_modes);
^

/home/qie/softs/ros_slam/Pangolin/src/video/drivers/openni2.cpp:660:79: error: invalid new-expression of abstract class type ‘pangolin::OpenNi2Video’
nivid = new OpenNi2Video(default_dim, default_roi, default_fps);
^

rc/sdf_loader.cpp: In member function 'void SDFloader::add_shape(std::istringstream&)':
src/sdf_loader.cpp:95:58: error: invalid new-expression of abstract class type 'box'
&scene_.materials[mat]));
^

class SDFloader {
public:
SDFloader();
~SDFloader();

Scene const& scene() const;
void read(std::string file);

private:
void add_material(std::istringstream&);
void add_shape(std::istringstream&);
void add_light(std::istringstream&);
void add_camera(std::istringstream&);
void apply_transformation(std::istringstream&);

private:
Scene scene_;
};

void SDFloader::add_shape(std::istringstream& iss) {

std::string name;
iss >> name;

if(name == "box") {
double x1,y1,z1,x2,y2,z2;
std::string mat;
iss >> name >> x1 >> y1 >> z1 >> x2 >> y2 >> z2 >> mat;
scene_.shapes.insert(new box(point(x1,y1,z1),
point(x2,y2,z2),
name,
&scene_.materials[mat]));
}

Решение

Другие решения

class Base
{
public:
virtual void foo(int a, const int b) = 0;
}
class D: public Base
{
public:
void foo(int a, int b){};
}

using QueuePtr = std::unique_ptr<Queue>;