while(in.eof()!= 1){
		in.read((char *)&st,sizeof(st));
		st.showData();		
	}

#include <iostream>
#include <conio.h>
#include <fstream>
#include <string.h>
using namespace std;
 
class Student{
private:
	char name[30];
	int id;
	int rollNo;
 
public:
	Student(){}
	Student(char *n,int i, int r){
		strcpy_s(name,n);
		id = i;
		rollNo = r;
	}
	void getData(){
		cout << "Enter Name    : "; cin >> name;
		cout << "Enter Id      : "; cin >> id;
		cout << "Enter Roll No : "; cin>> rollNo;
	}
 
	void showData(){
		cout << "Student Detail---------------"<<endl;
		cout << "Name      : " << name << endl;
		cout << "Id Number : " <<id << endl;
		cout << "Roll No   : " <<rollNo << endl;
	}
};
 
void outData(Student &st){
	ofstream out;
	out.open("obj.txt",ios::app | ios::binary);
	out.write((char *)&st,sizeof(st));
	out.close();
}
 
void inData(Student st){
	int count =0;
	ifstream in;
	in.open("obj.txt",ios::in|ios::binary);
	while(in.eof()!= 1){
		in.read((char *)&st,sizeof(st));
		st.showData();		
	}
 
	in.close();
 
}
int main()
{
 
	Student st;
	inData(st);
 
	return 0;
}

while(in.read((char *)&st,sizeof(st)))
{		
   st.showData();			
}