PROGRAM FOR EXHIBITING VARIOUS FILE I/O AND FILE RELATED OPERATORS

#include<iostream>
#include<fstream>
using namespace std;

// define a class to store student data
class student {
   int roll;
   char name[30];
   float marks;
public:
   student() { }
   void getData(); // get student data from user
   void displayData(); // display data
};

void student :: getData() {
   cout << "\nEnter Roll No. : ";
   cin >> roll;
   cin.ignore(); // ignore the newline char inserted when you press enter
   cout << "Enter Name : ";
   cin.getline(name, 30);
   cout << "Enter Marks : ";
   cin >> marks;
}

void student :: displayData() {
   cout << "\nRoll No. : " << roll << endl;
   cout << "Name : " << name << endl;
   cout << "Marks : " << marks << endl;
}

int main() {
   student s[3]; // array of 3 student objects
   fstream file;
   int i;

   file.open("objects.txt", ios :: out); // open file for writing
   cout << "\nWriting Student information to the file :- " << endl;
   for (i = 0; i < 3; i++) {
      s[i].getData();
      // write the object to a file
      file.write((char *)&s[i], sizeof(s[i]));
   }
   file.close(); // close the file

   file.open("objects.txt", ios :: in); // open file for reading
   cout << "\nReading Student information to the file :- " << endl;
   for (i = 0; i < 3; i++) {
      // read an object from a file
      file.read((char *)&s[i], sizeof(s[i]));
      s[i].displayData();
   }
   file.close(); // close the file

   return 0;
}