C++

#include<iostream>
#include<fstream>

using namespace std;
//Creating a class student
class student
{
private:
int roll_no;
char name[100];
char dept_name[100];
int marks[5];
public:
void get_input();
void calculate();
void print_data();
void filein(int);
void fileout();
int countstudent();
};
//This function is used to read the student records from file Student.dat
void student::filein(int pn)
{
ifstream infile;
infile.open("Student.dat",ios::binary);
infile.seekg(pn*sizeof(student));
infile.read((char*) this,sizeof(*this));
}
//This function is used to write the student records into file Student.dat. If previous data exists new records are appended
void student::fileout()
{
ofstream outfile;
outfile.open("Student.dat",ios::app|ios::binary);
get_input();
outfile.write((char*)this,sizeof(*this));
}
//This function is used to count number of students recorded in the file
int student::countstudent()
{
ifstream infile;
infile.open("Student.dat",ios::binary);
infile.seekg(0,ios::end);
int n=infile.tellg()/sizeof(student);
return n;
}
//This function is used to get all the inputs
void student::get_input()
{
cout<<"\nEnter roll-no:";
cin>>roll_no;
cout<<"\nEnter name:";
getchar();
cin.getline(name,100);
cout<<"\nEnter department name:";
cin.getline(dept_name,100);
}

//This function is used to print all the information
void student::print_data()
{
cout<<"\n\nRoll:"<<roll_no;
cout<<"\n\nName:"<<name;
cout<<"\n\nDepartment:"<<dept_name;
}


int main()
{
student s;
int n;
char ch;
do
{
cout<<"Enter data for student\n-----------------------------------------\n";
s.fileout();//Read from user and write to file
cout<<"Enter another(Y/N):";
cin>>ch;
}while(ch=='Y'||ch=='y');
n=s.countstudent();
for(int i=n-1;i>=0;i--)
{
cout<<"\n\nStudent "<<i+1<<"\n----------------";
s.filein(i);//Read from file
s.print_data();//Print records in reverse order
}
return 0;
}