STUDENT MANAGEMENT SYSTEM IN CPP WITH FILE HANDLING - WORKING CODE

//Students data project with file stream
#include<fstream.h>
#include<conio.h>
#include<process.h>
#include<stdio.h>
class Student
{
int rollno;
char name[20];
int Class;
int marks;
char grade;
public:
void getdata();
void display();
int getmarks() {return marks;}
int getno() {return rollno;}
int getClass() {return Class;}
}s;

void Student::getdata()
{
cout<<"Enter Roll No. : ";
cin>>rollno;
cout<<"Enter Name     : ";
cin>>name;
// cin.getline(name,20);
// gets(name);
cout<<"Enter Class    : ";
cin>>Class;
cout<<"Enter Marks    : ";
cin>>marks;
    if(marks>=75) grade='A';
else if(marks>=60) grade='B';
else if(marks>=50) grade='C';
else if(marks>=35) grade='D';
else grade='F';
}
void Student::display()
{
cout<<"=================================================\n";
cout<<"Roll No. : "<<rollno<<"\tName  : "<<name<<"\n";
cout<<"Class    : "<<Class <<"\tMarks : "<<marks<<"\tGrade : "<<grade<<"\n";
// cout<<"=================================================\n";
}

//Prototyping of functions for menu
void menu();
void search();
void add();
void displayall();
void Classwise();
void Modify();
void Delete();
void options();
void Trash();
void SizeofFile();
int main()
{
int n,rno,i;
fstream fio("stud.dat",ios::in|ios::out|ios::binary);
clrscr();
menu();
// fio.close();
getch();
return 0;
}

void options()
{
cout<<"\n\t...MENU OF PROGRAM...\n";
cout<<"\t0. EXIT....\n";
cout<<"\t1. Add the record...\n";
cout<<"\t2. Search the record...\n";
cout<<"\t3. Display all records...\n";
cout<<"\t4. Class wise records...\n";
cout<<"\t5. Modify the Record...\n";
cout<<"\t6. Delete the Record...\n";
cout<<"\t7. View Deleted Records...\n";
cout<<"\t8. View the Size of File...\n";
cout<<"\nEnter Your Choice  : ";
}

void menu()
{
int ch;
options();
cin>>ch;
while(ch)
{
 switch(ch)
 {
case 1: add(); break;
case 2: search(); break;
case 3: displayall(); break;
case 4: Classwise(); break;
case 5: Modify(); break;
case 6: Delete(); break;
case 7: Trash(); break;
case 8: SizeofFile(); break;
default: cout<<"Wrong Input please enter the correct value....";
 }
 system("pause");
 clrscr();
 options();
 cin>>ch;
}
}

void search()
{
ifstream fin("stud.dat",ios::in|ios::binary);
int rno,i=0;
char found='n';
cout<<"\nEnter Roll No. to be searched : ";
cin>>rno;

while(fin.read((char*)&s,sizeof(s)))
{
if(s.getno()==rno)
{
s.display();
found='y';
}
i++;
}
if(found=='n') cout<<"\nThe Roll No. "<<rno<<" is not in the file...\n";
fin.close();
}

//For Displaying the all data of the students.
void displayall()
{
ifstream fin("stud.dat",ios::in|ios::binary);
while(fin.read((char*)&s,sizeof(s)))
{
s.display();
}
fin.close();
// int x=gcount();
// cout<<"\n"<<x<<" Bytes read from file...\n";
}

//For adding the data into the file.
void add()
{
char ch='y';
ofstream fout("stud.dat",ios::out|ios::app|ios::binary);
while(ch=='y'||ch=='Y')
{
s.getdata();
fout.write((char*)&s,sizeof(s));
cout<<"\nDo you want to add more : ";
cin>>ch;
}
cout<<"\nData Appended and Transferred to file...\n";
fout.close();
}

void Classwise()
{
ifstream fin("stud.dat",ios::in|ios::binary);
int std;
char found='n';
cout<<"\nEnter the class to be searched : ";
cin>>std;

while(fin.read((char*)&s,sizeof(s)))
{
if(s.getClass()==std)
{
s.display();
found='y';
}
}
if(found=='n') cout<<"\nThe Class "<<std<<" is not in the file...\n";
fin.close();
}

void Modify()
{
fstream fio("stud.dat",ios::in|ios::out|ios::binary);
int rno;
char found='n';
fio.seekg(0);
cout<<"\nEnter the Roll No. whose record is to be modified: ";
cin>>rno;

while(fio)
// while(fio.read((char*)&s,sizeof(s)))
{
// fio.read((char*)&s,sizeof(s));
 int loc=fio.tellg();
 fio.read((char*)&s,sizeof(s));
//  fio.read((char*)&s,sizeof(s));
 if(s.getno()==rno)
 {
s.getdata();
found='y';
fio.seekg(loc);
fio.write((char*)&s,sizeof(s));
cout<<"\nYour record of Roll No. "<<rno
   <<" has been updated....";
 }
}
if(found=='n') cout<<"\nThe Class "<<rno<<" is not in the file...\n";
fio.close();
}

void Delete()
{
int rno;
char found='n';
fstream fio("stud.dat",ios::in|ios::out|ios::binary|ios::app);
ofstream fout("temp.dat",ios::out|ios::binary|ios::app);
ofstream out("trash.dat",ios::out|ios::binary|ios::app);

cout<<"\nEnter the Roll No. whose record is to be deleted: ";
cin>>rno;

while(fio.read((char*)&s,sizeof(s)))
{
if(s.getno()==rno)
{
out.write((char*)&s,sizeof(s));
found='y';
}
else
{
fout.write((char*)&s,sizeof(s));
}
}
if(found=='n') cout<<"\nThe Roll No."<<rno<<" is not in the file...\n";
fio.close();
fout.close();
remove("stud.dat");
rename("temp.dat","stud.dat");
}

void Trash()
{
ifstream fin("trash.dat",ios::in|ios::binary);
// ofstream fout("stud.dat",ios::out|ios::binary|ios::app);
while(fin.read((char*)&s,sizeof(s)))
{
s.display();
// fout.write((char*)&s,sizeof(s));
}
fin.close();
// fout.close();
//Commented lines are for restoring the deleted files to stud.dat file.
}
void SizeofFile()
{
fstream fio("stud.dat",ios::in|ios::out|ios::binary);
int size;
int begin,last;
begin=fio.tellg();
while(fio.read((char*)&s,sizeof(s)));
last=fio.tellg();
fio.close();
cout<<"\nThe Size of Stud.dat file is : "<<(last-begin)<<" bytes...\n";
}