Operator Overloading

Operator Overloading is a concept that uses only in C++. A simple way to say about Operator Overloading is doing or setting to do arithmetic operations( Addition, Subtraction, Multiplication, Division, etc.....) to Objects. If it is a normal variable it is easy to do this operations.( Eg: A = B + C which A,B and C are integers). What happens if A, B and C were Objects. If they are objects they also individually have some variables. So we cant use normal arithmetic to them. Eg:

class test
{
  int a,b,c;

  public:

  void print();
};

Assume that A,B and C are objects of class test. What will happens if we use this kind of operation A = B + C. Program doesn't know what to do in the object. Shall B.a + C.a must assign to A.a or B.a + B.b + B.c must assign to A.a?? Program doesn't know. So we have to tell the program what to do if this happens. That is what called Operator Overloading. This is just a simple definition. The following program is mostly about Operator Overloading. But it contains about friend functions, constructors, destructors and some about function overloading.

//Operator Overloading

#include 
#include 

using namespace std;

class dimension
{
 int x, y, z;

public:

 // Constructos And Destructors

 dimension();
 dimension( int );
 ~dimension();

 // Member Functions

 void display() // Inline
 {
  cout << x << " " << y << " " << z;
 }

 void input();

 // Operator Overloading

 friend dimension operator - ( dimension );
 friend dimension operator - ( dimension, dimension );

 dimension operator + ( dimension );

};

dimension :: dimension()
{
 x = 0;
 y = 0;
 z = 0;
}

dimension :: dimension( int a )
{
 x = a;
 y = 0;
 z = 0;
}

dimension :: ~dimension()
{
 cout << " ";
}

void dimension :: input()
{
 cout << "Enter Values for x, y and z:";
 cin >> x >> y >> z;
}

dimension operator - ( dimension a )
{
 dimension temp;

 temp.x = -a.x;
 temp.y = -a.y;
 temp.z = -a.z;

 return temp;
}

dimension operator - ( dimension a, dimension b )
{
 dimension temp;

 temp.x = ( a.x - b.x );
 temp.y = ( a.y - b.y );
 temp.z = ( a.z - b.z );

 return temp;
}

dimension dimension :: operator + ( dimension a )
{
 dimension temp;

 temp.x = ( x + a.x );
 temp.y = ( y + a.y );
 temp.z = ( z + a.z );

 return temp;
}

void main()
{
 dimension A, B, C, D, E;
 
 cout << "Enter Values For A and B\n";

 A.input();
 B.input();

 C = -A;

 C.display();

 D = A + B;

 D.display();

 E = B - A;

 E.display();

 getch();

}