C++/Overload/Unary Operator
Overload a unary operator.
#include <iostream>
using namespace std;
class MyClass {
int x, y, z;
public:
MyClass() {
x = y = z = 0;
}
MyClass(int i, int j, int k) {
x = i;
y = j;
z = k;
}
MyClass operator+(MyClass op2);
MyClass operator=(MyClass op2);
MyClass operator++();
void show() ;
} ;
MyClass MyClass::operator+(MyClass op2)
{
MyClass temp;
temp.x = x + op2.x;
temp.y = y + op2.y;
temp.z = z + op2.z;
return temp;
}
MyClass MyClass::operator=(MyClass op2)
{
x = op2.x; // These are integer assignments
y = op2.y; // and the = retains its original
z = op2.z; // meaning relative to them.
return *this;
}
MyClass MyClass::operator++()
{
x++; // increment x, y, and z
y++;
z++;
return *this;
}
void MyClass::show()
{
cout << x << ", ";
cout << y << ", ";
cout << z << endl;
}
int main()
{
MyClass a(1, 2, 3), b(10, 10, 10), c;
a.show();
b.show();
c = a + b;
c.show();
c = a + b + c;
c.show();
c = b = a;
c.show();
b.show();
++c;
c.show();
return 0;
}
Use a member function to overload the unary -.
#include <iostream>
using namespace std;
class three_d {
int x, y, z;
public:
three_d() { x = y = z = 0; }
three_d(int i, int j, int k) { x = i; y = j; z = k; }
three_d operator+(three_d rh_op);
three_d operator+(int rh_op);
three_d operator-(three_d rh_op);
three_d operator=(three_d rh_op);
bool operator==(three_d rh_op);
three_d operator-();
friend ostream &operator<<(ostream &strm, three_d op);
friend three_d operator+(int lh_op, three_d rh_op);
};
three_d three_d::operator+(three_d rh_op)
{
three_d temp;
temp.x = x + rh_op.x;
temp.y = y + rh_op.y;
temp.z = z + rh_op.z;
return temp;
}
three_d three_d::operator+(int rh_op)
{
three_d temp;
temp.x = x + rh_op;
temp.y = y + rh_op;
temp.z = z + rh_op;
return temp;
}
three_d three_d::operator-(three_d rh_op)
{
three_d temp;
temp.x = x - rh_op.x;
temp.y = y - rh_op.y;
temp.z = z - rh_op.z;
return temp;
}
three_d three_d::operator-()
{
three_d temp;
temp.x = -x;
temp.y = -y;
temp.z = -z;
return temp;
}
three_d three_d::operator=(three_d rh_op)
{
x = rh_op.x;
y = rh_op.y;
z = rh_op.z;
return *this;
}
bool three_d::operator==(three_d rh_op)
{
if( (x == rh_op.x) && (y == rh_op.y) && (z == rh_op.z) )
return true;
return false;
}
ostream &operator<<(ostream &strm, three_d op) {
strm << op.x << ", " << op.y << ", " << op.z << endl;
return strm;
}
three_d operator+(int lh_op, three_d rh_op) {
three_d temp;
temp.x = lh_op + rh_op.x;
temp.y = lh_op + rh_op.y;
temp.z = lh_op + rh_op.z;
return temp;
}
int main()
{
three_d objA(1, 2, 3), objB(10, 10, 10), objC;
cout << "This is objA: " << objA;
cout << "This is objB: " << objB;
objC = -objA;
cout << "This is -objA: " << objC;
objC = objA + objB;
cout << "objA + objB: " << objC;
objC = objA - objB;
cout << "objA - objB: " << objC;
objC = objA + 10;
cout << "objA + 10: " << objC;
objC = 100 + objA;
cout << "100 + objA: " << objC;
if(objA == objB)
cout << "objA is equal to objB.\n";
else
cout << "objA is not equal to objB.\n";
return 0;
}