Operator overload: new, delete, new[] and delete[]

 

#include <iostream>

#include <cstdlib>

#include <new>

using namespace std;

class MyClass {

  int x, y;

public:

  MyClass() {

     x = y = 0;

  }
  
  MyClass(int lg, int lt) {

    x = lg;

    y = lt;
  }

  void show() {

    cout << x << " ";

    cout << y << endl;

  }

  void *operator new(size_t size);

  void operator delete(void *p);

  void *operator new[](size_t size);

  void operator delete[](void *p);
};

// overloaded new operator
void *MyClass::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 operator overloaded
void MyClass::operator delete(void *p)
{
  
  cout << "In overloaded delete.\n";
  
  free(p);
}

// new operator overloaded for arrays.
void *MyClass::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 operator overloaded for arrays.
void MyClass::operator delete[](void *p)
{
  cout << "Freeing array using overloaded delete[]\n";
  
  free(p);
}

int main()
{
  MyClass *objectPointer1, *objectPointer2;

  int i;

  try {
  
    objectPointer1 = new MyClass (10, 20); 
  
  } catch (bad_alloc xa) {
  
    cout << "Allocation error for objectPointer1.\n";
  
    return 1;;
  }

  try {
  
  
    objectPointer2 = new MyClass [10];               // allocate an array
  
  } catch (bad_alloc xa) {
  
    cout << "Allocation error for objectPointer2.\n";
  
    return 1;;
  }

  objectPointer1->show();
  
  for( i = 0; i < 10; i++)
    objectPointer2[i].show();

  delete objectPointer1;                             // free an object
  delete [] objectPointer2;                          // free an array

  return 0;
}

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Operator overload: new, delete, new[] and delete[] : Index « Overload « C++

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