c++ program for reading and writing of class objects

Here is an example for reading and writting of class object in c++ : 

#include<iostream.h>

#include<conio.h>

#include<fstream.h>

class student

{

int roll_no;

char name[20];

public:

void read()

{

cin>>roll_no>>name;

}

void show()

{

cout<<roll_no<<name;

}

};

void main()

{

clrscr();

student s1;

s1.read();

ofstream out("stu.txt",ios::binary);

out.write((char*)&s1,sizeof(s1));

ifstream in("stu.txt",ios::binary);

in.read((char*)&s1,sizeof(s1));

s1.show();

getch();

}

Output of program is: