## Introduction

Operator overloading is one of the most fascinating features of c++. By overloading operator we can give additional meaning to operators like +,-,*,<=,>= etc. which by default are supposed to work only on standard data types like int, float etc.

The operators that cannot be overloaded are ., ::, ? and :.

Here we are creating simple class example for operator overloading.

#include<iostream.h>
#include<conio.h>
class xy
{
private:
int x,y;
public:
=
xy()
{ x=y=0; }
xy(int i,int j)
{x=i;y=j;}
xy(xy &z)
{x=z.x;y=z.y;}
=
xy operator-();
xy operator++();
xy operator--();
xy operator++(int);
xy operator--(int);
=
xy operator+(xy &);
xy operator-(xy &);
xy operator*(xy &);
xy operator/(xy &);
xy operator%(xy &);
xy operator=(xy &);
xy operator+=(xy &);
xy operator-=(xy &);
xy operator*=(xy &);
xy operator/=(xy &);
xy operator%=(xy &);
=
int operator<(xy &);
int operator>(xy &);
int operator==(xy &);
int operator!=(xy &);
int operator<=(xy &);
int operator>=(xy &);
=
friend ostream&operator<<(ostream&, xy&);
friend istream&operator>>(istream&, xy&);
};
</conio.h></iostream.h>

Function `operator-()`

for return absolute value.

xy xy::operator-()
{
if(x<0){x*=-1;}
if(y<0){y*=-1;}
return *this;
}

Function of unary operators.

xy xy::operator++()
{
++x;++y;
return *this;
}
xy xy::operator--()
{
--x;--y;
return *this;
}
xy xy::operator++(int)
{
x++;y++;
return *this;
}
xy xy::operator--(int)
{
x--;y--;
return *this;
}

Function of binary operators.

xy xy::operator+(xy &z)
{
xy t;
t.x=x+z.x;
t.y=y+z.y;
return t;
}
xy xy::operator-(xy &z)
{
xy t;
t.x=x-z.x;
t.y=y-z.y;
return t;
}
xy xy::operator*(xy &z)
{
xy t;
t.x=x*z.x;
t.y=y*z.y;
return t;
}
xy xy::operator=(xy &z)
{
x=z.x;y=z.y;
return *this;
}
xy xy::operator/(xy &z)
{
xy t;
t.x=x/z.x;
t.y=y/z.y;
return t;
}
xy xy::operator%(xy &z)
{
xy t;
t.x=x%z.x;
t.y=y%z.y;
return t;
}
xy xy::operator+=(xy &z)
{
xy t;
t.x=x+z.x;
t.y=y+z.y;
return t;
}
xy xy::operator-=(xy &z)
{
xy t;
t.x=x-z.x;
t.y=y-z.y;
return t;
}
xy xy::operator*=(xy &z)
{
xy t;
t.x=x*z.x;
t.y=y*z.y;
return t;
}
xy xy::operator/=(xy &z)
{
xy t;
t.x=x/z.x;
t.y=y/z.y;
return t;
}
xy xy::operator%=(xy &z)
{
xy t;
t.x=x%z.x;
t.y=y%z.y;
return t;
}

Function of insertion(`>>`

) & extraction(`<<`

) operators.

ostream&operator<<(ostream &o, xy &z)
{
o<<endl<<"(x: "<<z.x<<",y: "<<z.y<<")";
return o;
}
istream&operator>>(istream &i, xy &z)
{
cout<<endl<<"Enter X & Y: ";
i>>z.x>>z.y;
return i;
}

main program to call some overloaded operators.

void main()
{
clrscr();
xy a,b(10,20),c;
cin>>a;
cout<<a<<b;
cout<<endl<<"a+b:";
c=a+b;
cout<<c;
cout<<endl<<"a-b:";
c=a-b;
cout<<c;
cout<<endl<<"a*b:";
c=a*b;
cout<<c;
cout<<endl<<"a/b:";
c=a/b;
cout<<c;
cout<<endl<<"a%b:";
c=a%b;
cout<<c;
cout<<endl<<"c+=b:";
c=c+=b;
cout<<c;
getch();
}

The calling function internal layout is `c=a.operator+(b);`

but C++ provided user friendly features operator overloading, so our calling layout is `c=a+b`

like normal default data types operations.