Unary Operator Overloading

#include<iostream.h>

#include<constream.h>

class num

 {

     private:

   int a,b,c,d;

     public:

   num(int j, int k, int m, int l)

     {

a=j;

b=k;

c=m;

d=l;

}

   void show(void);

   void operator ++();

   void operator --();

 };

void num::show()

 {

cout<<"A= "<<a<<"B= "<<b<<"C= "<<c<<"D= "<<d;

 }

void num::operator++()

 {

++a;++b;++c;++d;

 }

void num::operator--()

 {

--a;--b;--c;--d;

 }

void main()

 {

clrscr();

num X(3,2,5,7);

cout<<"\n Before increment of X :";

X.show(); 

++X;

cout<<"\n After increment of X :";

X.show();

cout<<"\n Before decrement of X :";

X.show();

--X;

cout<<"\n  After decrement of X :";

X.show(); 

getch();

 }