Prog-2

#include<stdio.h>

#include<stdlib.h>

#include<iostream.h>

#include<fstream.h>

#include<stdlib.h>

#include<conio.h>

#include<string.h>

#include<iomanip.h>

class student

{

  public:char name[15],usn[15],age[5],sem[5],branch[15],buffer[45];

};

student s2[100];

void writeRecord()      //Function to add record to file

{

 fstream app;

 student s;

 app.open("student.txt",ios::app); //Open file in append mode

 if(!app)

 {

   cout<<"cannot open the file in output mode";

   getch();

   exit(0);

 }

 cout<<"\nEnter the student name       = ";

 cin>>s.name;

 cout<<"\nEnter the usn                = ";

 cin>>s.usn;

 cout<<"\nEnter the age                = ";

 cin>>s.age;

 cout<<"\nEnter the sem                = ";

 cin>>s.sem;

 cout<<"\nEnter the branch             = ";

 cin>>s.branch;

 //packing the information

 strcpy(s.buffer,s.name);

 strcat(s.buffer,"|");

 strcat(s.buffer,s.usn);

 strcat(s.buffer,"|");

 strcat(s.buffer,s.age);

 strcat(s.buffer,"|");

 strcat(s.buffer,s.sem);

 strcat(s.buffer,"|");

 strcat(s.buffer,s.branch);

 int count=strlen(s.buffer);

 for(int k=0;k<45-count;k++)

 strcat(s.buffer,"!");

 strcat(s.buffer,"\n");

 app<<s.buffer;           //writing the packed information to buffer

 app.close();

}

void search()

{

   fstream in;

   char usn[15],extra[45];

   in.open("student.txt",ios::in);

  if(!in)

  {

    cout<<"\nUnable to open the file in input mode";

    getch();

    exit(0);

  }

  cout<<"\nEnter the record's usn you want to search = ";

  cin>>usn;

  student s;

  //Unpacking the record

  while(!in.eof())

  {

   in.getline(s.name,15,'|');

   in.getline(s.usn,15,'|');

   in.getline(s.age,5,'|');

   in.getline(s.sem,5,'|');

   in.getline(s.branch,15,'!');

   in.getline(extra,45,'\n');

   if(strcmp(s.usn,usn)==0)

   {

    cout<<"\nRecord found";

    cout<<"\n"<<s.name<<"\t"<<s.usn<<"\t"<<s.age<<"\t"<<s.sem<<"\t"<<s.branch;

    getch();

    return;

   }

  }

  cout<<"\nRecord not found";

  getch();

  return;

}

void displayFile()

{

 student s;

 int c,i;

 char extra[45];

 fstream in;

 in.open("student.txt",ios::in);

 if(!in)

 {

   cout<<"\ncannot open the file in output mode";

   getch();

   exit(0);

 }

 i=0;

 printf("Name\t\tUsn\t\tAge\t\tSem\t\tBranch\n");

 while(!in.eof())

 {

  in.getline(s.name,15,'|');

  in.getline(s.usn,15,'|');

  in.getline(s.age,5,'|');

  in.getline(s.sem,5,'|');

  in.getline(s.branch,15,'!');

  in.getline(extra,45,'\n');

  printf("\n%s\t\t%s\t\t%s\t\t%s\t\t%s",s.name,s.usn,s.age,s.sem,s.branch);

  i++;

 }

 in.close();

 getch();

}

void modify()

{

  fstream in;

  char usn[15],buffer[45],extra[45];

  int i,j;

  student s1[100];

  in.open("student.txt",ios::in);

  if(!in)

  {

    cout<<"\nUnable to open the file in input mode";

    getch();

    exit(0);

  }

  cout<<"\nEnter the usn";

  cin>>usn;

   i=0;

   //Loading the file to Main memory

  while(!in.eof())

  {

  in.getline(s1[i].name,15,'|');

  in.getline(s1[i].usn,15,'|');

  in.getline(s1[i].age,5,'|');

  in.getline(s1[i].sem,5,'|');

  in.getline(s1[i].branch,15,'!');

  in.getline(extra,45,'\n');

  i++;

  }

 i--;

 for(j=0;j<i;j++)

 {

  if(strcmp(usn,s1[j].usn)==0)

  {

    cout<<"\nThe old values of the record with usn "<<usn<<" are ";

    cout<<"\nname   = "<<s1[j].name;

    cout<<"\nusn    = "<<s1[j].usn;

    cout<<"\nage    = "<<s1[j].age;

    cout<<"\nsem    = "<<s1[j].sem;

    cout<<"\nbranch = "<<s1[j].branch;

    cout<<"\nEnter the new values \n";

    cout<<"\nname   = ";  cin>>s1[j].name;

    cout<<"\nusn    = ";  cin>>s1[j].usn;

    cout<<"\nage    = ";  cin>>s1[j].age;

    cout<<"\nsem    = ";  cin>>s1[j].sem;

    cout<<"\nbranch = ";  cin>>s1[j].branch;

    break;

  }

 }

 if(j==i)

 {

  cout<<"\nThe record with usn "<<usn<<" is not present";

  getch();

  return;

 }

 in.close();

 fstream out1;

 out1.open("student.txt",ios::out);

 if(!out1)

 {

  cout<<"\nUnable to open the file in output mode";

  getch();

  return;

 }

 for(j=0;j<i;j++)

 {

   strcpy(buffer,s1[j].name);

   strcat(buffer,"|");

   strcat(buffer,s1[j].usn);

   strcat(buffer,"|");

   strcat(buffer,s1[j].age);

   strcat(buffer,"|");

   strcat(buffer,s1[j].sem);

   strcat(buffer,"|");

   strcat(buffer,s1[j].branch);

  int count=strlen(buffer);

  for(int k=0;k<45-count;k++)

  strcat(buffer,"!");

   strcat(buffer,"\n");

   out1<<buffer;

 }

  out1.close();

}

void main()

{

 fstream in;

 fstream out;

 int choice;

 out.open("student.txt",ios::out);

 if(!in)

 {

   cout<<"\n\ncannot open the file in output mode";

   getch();

   exit(0);

 }

 out.close();

 for(;;)

 {

 clrscr();

 cout<<"\n0:exit";

 cout<<"\n1:write to file";

 cout<<"\n2:display the file";

 cout<<"\n3:modify the file";

 cout<<"\n4:search";

 cout<<"\n\nEnter the choice";

 cin>>choice;

 switch(choice)

 {

  case 1:writeRecord();break;

  case 2:displayFile();break;

  case 3:modify();break;

  case 4:search();break;

  case 0:exit(0);

  default:cout<<"\nInvalid input....";break;

 }

 }

}