File Ops

#include "heading.h"
class student
{
 char gr;
 int marks[5],total,per;
 public:
 char name[30];
 void getData()
 {
  cout<<"Enter Name:";
  cin>>name;
  cout<<"Enter Marks:";
  for(int i=0;i<5;i++)
  {
   cin>>marks[i];
  }
  total=marks[0]+marks[1]+marks[2]+marks[3]+marks[4];
  per=total/5;
  if(per>90)
   gr='A';
  else if(per>70)
   gr='B';
  else if(per>50)
   gr='C';
  else
   gr='D';
 }
 void showData()
 {
  cout<<"Name:"<<name<<endl;
  cout<<"Percentage:"<<per<<"%";
  cout<<"Grade:"<<gr<<endl;
 }
};


student obj;
int pos;
int p=0;

void menu()
{
 cout<<"\t\t\t\tFile Operations"<<endl;
 cout<<"\t\t\t\t~~~~~~~~~~~~~~~"<<endl;
 cout<<"1.Display"<<endl;
 cout<<"2.Append"<<endl;
 cout<<"3.Modify"<<endl;
 cout<<"4.Search"<<endl;
 cout<<"5.Insert"<<endl;
 cout<<"6.Delete"<<endl;
 cout<<"7.Exit"<<endl;
 cout<<"Your Choice:";
}

void append()
{
 obj.getData();
 ofstream ofile;
 ofile.open("grade.txt",ios::app);
 ofile.write((char *)&obj,sizeof(student));
 ofile.close();
}

void display()
{
 ifstream ifile;
 ifile.open("grade.txt");
 while(!ifile.eof())
 {
  ifile.read((char *)&obj,sizeof(student));
  obj.showData();
  cout<<endl;
 }
 ifile.close();
}

void search(char nam[])
{
 ifstream ifile;
 ifile.open("grade.txt");
 while(!ifile.eof())
 {
  ifile.read((char *)&obj,sizeof(student));
  if(strcmp(nam,obj.name)==0)
  {
   p=1;
   obj.showData();
   pos=ifile.tellg();
  }
 }
 if(p==0)
 {
  cout<<"\nError 404:Name not found.";
  cout<<"\nContact Admin at 9790770778";
 }
 ifile.close();
}

void modify()
{
 ofstream ofile("grade.txt",ios::ate);
 int epos;
 char name[30];
 cout<<"Enter name to modify:"<<endl;
 cin>>name;
 cout<<endl;
 search(name);
 if(p!=0)
 {
  epos=pos-sizeof(student);
  obj.getData();
  ofile.seekp(epos);
  ofile.write((char *)&obj,sizeof(student));
  ofile.close();
 }
}

void ddelete()
{
 int xpos,npos=0;
 ofstream ofile("temp.txt");
 ifstream ifile("grade.txt");
 char name[30];
 display();
 cout<<"Input Name you want to delete:";
 cin>>name;
 search(name);
 xpos=pos-sizeof(student);
 while(npos!=xpos)
 {
  ifile.read((char *)&obj,sizeof(student));
  ofile.write((char *)&obj,sizeof(student));
  npos=ifile.tellg();
 }
 xpos=xpos+sizeof(student);
 ifile.seekg(xpos);
 while(!ifile.eof())
 {
  ifile.read((char *)&obj,sizeof(student));
  ofile.write((char *)&obj,sizeof(student));
 }
 ifile.close();
 ofile.close();
 remove("grade.txt");
 rename("temp.txt","grade.txt");
}

void insert()
{
 int npos=0;
 ofstream ofile("temp.txt");
 ifstream ifile("grade.txt");
 char name[30];
 display();
 cout<<"\nAfter what do you want to insert? :";
 cin>>name;
 cout<<endl;
 search(name);
 if(p!=0)
 {
  while(npos!=pos)
  {
   ifile.read((char *)&obj,sizeof(student));
   ofile.write((char *)&obj,sizeof(student));
   npos=ifile.tellg();
  }
  student obj2;
  obj2.getData();
  ofile.write((char *)&obj2,sizeof(student));
  ifile.seekg(npos);
  while(!ifile.eof())
  {
   ifile.read((char *)&obj,sizeof(student));
   ofile.write((char *)&obj,sizeof(student));
  }
  ifile.close();
  ofile.close();
 }
 remove("grade.txt");
 rename("temp.txt","grade.txt");
}

void main()
{
 char name[30];
 int ch;
 while(ch!=7)
 {
  getch();
  clrscr();
  menu();cin>>ch;
  switch(ch)
  {
   case 1:display();break;
   case 2:append();break;
   case 3:modify();break;
   case 4:cout<<"Enter Name to search:";
      cin>>name;
      search(name);break;
   case 5:insert();break;
   case 6:ddelete();break;
   case 7:bye();break;
  }
 }
}