Global new : new « Development « C++ Tutorial

1. C++ Tutorial
2. Development
3. new

#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;

class Point {
  int x, y;
public:
  Point() {}
  Point(int px, int py) {
    x = px;
    y = py;
  }

  void show() {
    cout << x << " ";
    cout << y << "\n";
  }
};

// Global new
void *operator new(size_t size)
{
  void *p;

  p =  malloc(size);
  if(!p) {
    bad_alloc ba;
    throw ba;
  }
  return p;
}

// Global delete
void operator delete(void *p)
{
  free(p);
}

int main()
{
  Point *p1, *p2;
  float *f;

  try {
    p1 = new Point (10, 20);
  } catch (bad_alloc xa) {
    cout << "Allocation error for p1.\n";
    return 1;;
  }

  try {
    p2 = new Point (-10, -20);
  } catch (bad_alloc xa) {
    cout << "Allocation error for p2.\n";
    return 1;;
  }

  try {
    f = new float; // uses overloaded new, too
  } catch (bad_alloc xa) {
    cout << "Allocation error for f.\n";
    return 1;;
  }

  *f = 10.10F;
  cout << *f << "\n";

  p1->show();
  p2->show();

  delete p1;
  delete p2;
  delete f;

  return 0;
}

10.1
10 20
-10 -20