Overload new, new[], delete, and delete[] for the Box class. - C++ Class

C++ examples for Class:Operator Overload

  1. HOME
  2. C++
  3. Class
  4. Operator Overload

Description

Overload new, new[], delete, and delete[] for the Box class.

Demo Code

#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;
class Box {/*from  w ww  .j  a v  a 2 s. c om*/
   int x, y, z; // 3-D coordinates
   public:
   Box() { x = y = z = 0; }
   Box(int i, int j, int k) { x = i; y = j; z = k; }
   // Set the coordinates of an object after it is created.
   void set(int i, int j, int k) { x = i; y = j; z = k; }
   // Overload new and delete for Box objects.
   void *operator new(size_t size);
   void operator delete(void *p);
   // Overload new[] and delete[] for Box arrays.
   void *operator new[](size_t size);
   void operator delete[](void *p);
   // Let the overloaded inserter be a friend.
   friend ostream &operator<<(ostream &strm, Box op);
};
// The Box inserter is a non-member operator function.
ostream &operator<<(ostream &strm, Box op) {
   strm << op.x << ", " << op.y << ", " << op.z << endl;
   return strm;
}
// Overload new for Box.
void *Box::operator new(size_t size)
{
   void *p;
   cout << "Using overloaded new for Box.\n";
   p =  malloc(size);
   if(!p) {
      bad_alloc ba;
      throw ba;
   }
   return p;
}
// Overload delete for Box.
void Box::operator delete(void *p)
{
   cout << "Using overloaded delete for Box.\n";
   free(p);
}
// Overload new[] for Box arrays.
void *Box::operator new[](size_t size)
{
   void *p;
   cout << "Using overloaded new[] for Box.\n";
   p =  malloc(size);
   if(!p) {
      bad_alloc ba;
      throw ba;
   }
   return p;
}
// Overload delete[] for Box arrays.
void Box::operator delete[](void *p)
{
   cout << "Using overloaded delete[] for Box.\n";
   free(p);
}
int main()
{
   Box *p1, *p2;
   int i;
   // Allocate a Box object.
   try {
      p1 = new Box (10, 20, 30);
   } catch (bad_alloc xa) {
      cout << "Allocation error for p1.\n";
      return 1;
   }
   cout << "Coordinates in the object pointed to by p1: " << *p1;
   // Free the object.
   delete p1;
   cout << endl;
   // Allocate a Box array.
   try {
      p2 = new Box [10]; // allocate an array
   } catch (bad_alloc xa) {
      cout << "Allocation error for p2.\n";
      return 1;
   }
   // Assign coordinates to three of p2's elements.
   p2[1].set(99, 88, 77);
   p2[5].set(-1, -2, -3);
   p2[8].set(56, 47, 19);
   cout << "Contents of a dynamic Box array:\n";
   for(i=0; i<10; i++) cout << p2[i];
   // Free the array.
   delete [] p2;
   return 0;
}

Result


Related Tutorials