Mega Code Archive
Demonstrate prefix and postfix ++
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#include <iostream>
using namespace std;
class ThreeD {
int x, y, z;
public:
ThreeD() { x = y = z = 0; }
ThreeD(int i, int j, int k) {x = i; y = j; z = k; }
ThreeD operator++(); // prefix version of ++
ThreeD operator++(int notused); // postfix version of ++
void show() ;
};
// Overload the prefix version of ++.
ThreeD ThreeD::operator++()
{
x++; // increment x, y, and z
y++;
z++;
return *this; // return altered value
}
// Overload the postfix version of ++.
ThreeD ThreeD::operator++(int notused)
{
ThreeD temp = *this; // save original value
x++; // increment x, y, and z
y++;
z++;
return temp; // return original value
}
// Show X, Y, Z coordinates.
void ThreeD::show( )
{
cout << x << ", ";
cout << y << ", ";
cout << z << "\n";
}
int main()
{
ThreeD a(1, 2, 3);
ThreeD b;
cout << "Original value of a: ";
a.show();
++a; // prefix increment
cout << "Value after ++a: ";
a.show();
a++; // postfix increment
cout << "Value after a++: ";
a.show();
b = ++a;
cout << "\nValue of a after b = ++a: ";
a.show();
cout << "Value of b after b = ++a: ";
b.show();
b = a++;
cout << "\nValue of a after b = a++: ";
a.show();
cout << "Value of b after b = a++: ";
b.show();
return 0;
}
Original value of a: 1, 2, 3
Value after ++a: 2, 3, 4
Value after a++: 3, 4, 5
Value of a after b = ++a: 4, 5, 6
Value of b after b = ++a: 4, 5, 6
Value of a after b = a++: 5, 6, 7
Value of b after b = a++: 4, 5, 6
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