Age calculation of a person implemented with c++

#include<iostream.h>

 class age

 {

            private: int y,m,d;

            public :

                                    age()

                                    {

           

                                    }

                                    age(int y1,int m1,int d1)

                                    {

                                                y=y1;m=m1;d=d1;

                                    }

                                    age operator - (age c)

                                    {

                                                age temp;

                                                if(d<31)

                                                {

                                                            d=d+30;

                                                            temp.d=d-c.d;

                                                            c.m=c.m+1;

                                                }

                                                if(m<13)

                                                {

                                                            m=m+12;

                                                            temp.m=m-c.m;

                                                            c.y=c.y+1;

                                                }

                                                temp.y=y-c.y;

            return temp;

                                    }

                                    void show()

                                    {

            cout<<"Age of the person=";

                                                cout<<endl<<"Year="<<y<<" month="<<m<<" day="<<d;

                                    }

 };

 void main()

 {

            age a1(2014,3,5),a2(1993,4,12),a3;

            a3=a1-a2;

            a3.show();

 }

Output: