allocates and frees an object and an array of objects of type loc. : object array « Class « C++ Tutorial






#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;
   
class loc {
  int longitude, latitude;
public:
  loc() {longitude = latitude = 0;}
  loc(int lg, int lt) {
    longitude = lg;
    latitude = lt;
  }
   
  void show() {
    cout << longitude << " ";
    cout << latitude << "\n";
  }
   
  void *operator new(size_t size);
  void operator delete(void *p);
   
  void *operator new[](size_t size);
  void operator delete[](void *p);
};
   
// new overloaded relative to loc.
void *loc::operator new(size_t size)
{
void *p;
   
  cout << "In overloaded new.\n";
  p =  malloc(size);
  if(!p) {
    bad_alloc ba;
    throw ba;
  }
  return p;
}
   
// delete overloaded relative to loc.
void loc::operator delete(void *p)
{
  cout << "In overloaded delete.\n";
  free(p);
}
   
// new overloaded for loc arrays.
void *loc::operator new[](size_t size)
{
  void *p;
   
  cout << "Using overload new[].\n";
  p =  malloc(size);
  if(!p) {
    bad_alloc ba;
    throw ba;
  }
  return p;
}
   
// delete overloaded for loc arrays.
void loc::operator delete[](void *p)
{
  cout << "Freeing array using overloaded delete[]\n";
  free(p);
}
   
int main()
{
  loc *p1, *p2;
  int i;
   
  try {
    p1 = new loc (10, 20); // allocate an object
  } catch (bad_alloc xa) {
    cout << "Allocation error for p1.\n";
    return 1;;
  }
   
  try {
    p2 = new loc [10]; // allocate an array
  } catch (bad_alloc xa) {
    cout << "Allocation error for p2.\n";
    return 1;;
  }
   
  p1->show();
 
  for(i=0; i<10; i++)
    p2[i].show();
   
  delete p1;    // free an object
  delete [] p2; // free an array
   
  return 0;
}








9.33.object array
9.33.1.Create an array of objects
9.33.2.An array of objects: call its method
9.33.3.Initialize an array of objects without referencing the constructor directly
9.33.4.Initialize an array of objects by referencing the constructor directly
9.33.5.Object array of derived classes
9.33.6.Allocate an array of objects using new operator
9.33.7.An array of pointers to objects
9.33.8.An array on the heap
9.33.9.Delete an array of objects
9.33.10.allocates and frees an object and an array of objects of type loc.