#include <assert.h>
#include <vector>

class myMatrix 
{
public:
  // element access
  int& operator()(unsigned int c)
    { 
      assert( (0<c)  && (c<=columns) );
      return *data[c];
    }
private:
  int columns;                
  vector<int>* data;
};

int main() 
{
  myMatrix m;
  m(1) = 19; 
  return 0; 
}