Mega Code Archive
Make op-- a friend; use reference
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#include <iostream>
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";
}
Point operator=(Point op2);
friend Point operator++(Point &op);
friend Point operator--(Point &op);
};
// Overload assignment for Point.
Point Point::operator=(Point op2)
{
x = op2.x;
y = op2.y;
return *this; // i.e., return object that generated call
}
// Now a friend; use a reference parameter.
Point operator++(Point &op)
{
op.x++;
op.y++;
return op;
}
// Make op-- a friend; use reference.
Point operator--(Point &op)
{
op.x--;
op.y--;
return op;
}
int main()
{
Point ob1(10, 20), ob2;
ob1.show();
++ob1;
ob1.show(); // displays 11 21
ob2 = ++ob1;
ob2.show(); // displays 12 22
--ob2;
ob2.show(); // displays 11 21
return 0;
}
10 20
11 21
12 22
11 21
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