Mega Code Archive
Overload new, new[], delete, and delete[] for the three_d class
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#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;
class three_d {
int x, y, z; // 3-D coordinates
public:
three_d() { x = y = z = 0; }
three_d(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 three_d objects.
void *operator new(size_t size);
void operator delete(void *p);
// Overload new[] and delete[] for three_d arrays.
void *operator new[](size_t size);
void operator delete[](void *p);
// Let the overloaded inserter be a friend.
friend ostream &operator<<(ostream &strm, three_d op);
};
// The three_d inserter is a non-member operator function.
ostream &operator<<(ostream &strm, three_d op) {
strm << op.x << ", " << op.y << ", " << op.z << endl;
return strm;
}
// Overload new for three_d.
void *three_d::operator new(size_t size)
{
void *p;
cout << "Using overloaded new for three_d.\n";
p = malloc(size);
if(!p) {
bad_alloc ba;
throw ba;
}
return p;
}
// Overload delete for three_d.
void three_d::operator delete(void *p)
{
cout << "Using overloaded delete for three_d.\n";
free(p);
}
// Overload new[] for three_d arrays.
void *three_d::operator new[](size_t size)
{
void *p;
cout << "Using overloaded new[] for three_d.\n";
p = malloc(size);
if(!p) {
bad_alloc ba;
throw ba;
}
return p;
}
// Overload delete[] for three_d arrays.
void three_d::operator delete[](void *p)
{
cout << "Using overloaded delete[] for three_d.\n";
free(p);
}
int main()
{
three_d *p1, *p2;
int i;
// Allocate a three_d object.
try {
p1 = new three_d (10, 20, 30);
} catch (bad_alloc xa) {
cout << "Allocation error for p1.\n";
return 1;
}
delete p1;
try {
p2 = new three_d [10];
} catch (bad_alloc xa) {
cout << "Allocation error for p2.\n";
return 1;
}
// Assign coordinates to three of p2's elements.
p2[1].set(9, 8, 7);
p2[5].set(-1, -2, -3);
p2[8].set(6, 7, 8);
cout << "Contents of a dynamic three_d array:\n";
for(i=0; i<10; i++) cout << p2[i];
delete [] p2;
return 0;
}
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