C++ search, delete/undelete, update functions

Question

stevensonnz 0 Newbie Poster

12 Years Ago

Basically the program is a database of student enrollments.

I cannot get the the search delete/undelete and update functions to work and need help asap. Need to implement a bool field to the delete / undelete

Please help

#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <conio.h>
#include <fstream>

using namespace std;

const char FILE_PATH[] = "E:\\iofile";
//------------------------------------------------------------------------------

struct Student
{
*** char names [ 16 ];
*** int other;
};

fstream MyFile ( FILE_PATH , ios :: binary | ios :: in | ios :: out );

void createFile();
void mainMenu();
void funcSwitch();
void addRecord();
int displayRecord();
void updateRecord();
void deleteRecord();
void printRecords();
int searchRecord();
//------------------------------------------------------------------------------
int main ( int argc, char* argv [] )
{
*** createFile();

*** mainMenu();
}
//------------------------------------------------------------------------------
void mainMenu()
{
*** cout << "Welcome to School Enrolment System" << endl << endl
*** *** * << "Please enter your selection: " << endl
*** *** * << "1.** Register - New Student (Add record)" << endl
*** *** * << "2.** Look Up - Existing Student (Display record)" << endl
*** *** * << "3.** Change Details (Update record)" << endl
*** *** * << "4.** Remove Student (Delete record)" << endl
*** *** * << "5.** Show all Students (Print all)" << endl
*** *** * << "6.** Exit " << endl << endl
*** *** * << "Selection: ";

*** funcSwitch();
}
//------------------------------------------------------------------------------
void funcSwitch()
{
** char choice;

*** choice = getch();
*** clrscr();
*** while ( choice != 54 )
** {
***** switch ( choice )
*** *** {
******** case '1' :
*********** addRecord();
*********** getch();
*** *** *** *** clrscr();
************** break;

******** case '2' :
*********** displayRecord();
*********** getch();
************** break;

******** case '3' :
*********** updateRecord();
*********** getch();
************** break;

******** case '4' :
*********** deleteRecord();
*********** getch();
************** break;

******** case '5' :
*********** printRecords();
*********** getch();
************** break;

******** case '6' :
*********** break;

******** default :
*** *** *** *** cout << choice << " is not a vaild choice" << endl << endl
*** *** *** *** *** * << "Press any key to choose again... ";
*********** getch();
*** *** *** *** clrscr();

***** }
***** mainMenu();
*** *** choice = getch();
*** *** clrscr();
** }
}
//------------------------------------------------------------------------------
void addRecord()
{
*** Student temp;

*** cout << "Welcome new Student!" << endl
*** *** * << "We're going to set you up with a new Enrolment..." << endl
*** *** * << "All we need is a few details, let's begin: " << endl;

*** cout << endl << "Please enter first name : ";
*** cin >> temp.names;



*** cout << endl << "Please enter your age : ";
*** cin >> temp.other;


*** MyFile.open ( FILE_PATH , ios :: binary | ios :: app | ios :: out );
*** MyFile.clear();
*** MyFile.write ( ( const char* ) &temp, sizeof ( Student ) );
*** MyFile.clear();
*** MyFile.close();
}
//------------------------------------------------------------------------------
int searchRecord()
{

*** return 0;
}
//------------------------------------------------------------------------------
int displayRecord()
{
*** Student temp;
*** int age;
*** int position;

*** cout << "Enter age of person you are seeking: ";
*** cin >> age;
*** clrscr();



*** MyFile.open ( FILE_PATH , ios :: binary | ios :: in );
*** MyFile.clear();
*** MyFile.seekp ( position * sizeof ( Student ), ios :: beg );
*** MyFile.read ( ( char* ) &temp, sizeof ( Student ) );

*** if ( age != temp.other )
*** {
*** *** cout << endl << "No record found. Press any key to continue...";
*** }
*** else
*** {
*** *** cout << "We found your record: " << endl << endl
*** *** *** * << "Name: " << temp.names << endl
*** *** *** * << "Age:* " << temp.other << endl;
*** }

*** *** *cout << endl << "Press any key to continue..." << endl;
*** *** *getch();
*** *** *clrscr();
*** *** *mainMenu();
*** *** *MyFile.close();
*** *** *return 0;

}
//------------------------------------------------------------------------------
void updateRecord()
{
*** Student temp;
*** time_t t;
*** char choice;
*** int position;

*** position = displayRecord ();

*** MyFile.open( FILE_PATH, ios :: binary | ios :: out );
*** MyFile.clear();

*** if( position != -1 )
*** {
*** *** cout << endl << "Do you want to Update this Record( y or n )";
*** *** choice = getch();
*** }

*** if( choice == 'y' )
*** {
*** *** cout << endl << "Enter name : ";
*** *** cin >> temp.names;

*** *** cout << endl << "And your age : ";
*** *** cin >> temp.other;




*** *** MyFile.open( FILE_PATH, ios :: binary | ios :: out );
*** *** MyFile.clear();
*** *** MyFile.seekp( position * sizeof( Student ), ios :: beg );
***** MyFile.clear();
*** *** MyFile.write( ( const char* ) &temp, sizeof( Student ) );
***** MyFile.close();
*** }
}


//------------------------------------------------------------------------------
void deleteRecord()
{

*** Student temp;
*** char choice;
*** int position;

*** -MyFile.open( FILE_PATH, ios :: binary | ios :: in | ios :: out );
*** MyFile.clear();
*** MyFile.seekp( position * sizeof( Student ), ios :: beg );
*** MyFile.read( ( char* )&temp, sizeof( Student ) );

*** cout << endl << endl;
*** cout << "Would you like to delete this record? Yes (y) or No (n): ";
*** cin >> choice;

*** choice = getch();

*** MyFile.seekp( position * sizeof( Student ), ios :: beg );
*** MyFile.write( ( const char* )&temp, sizeof( Student ) );

*** getch();
*** clrscr();
*** mainMenu();

*** MyFile.close();
}

//-----------------------------------------------------------------------------

void printRecords()
{
*** Student temp;

*** MyFile.open ( FILE_PATH , ios :: binary | ios :: in );
*** MyFile.clear();
*** MyFile.read ( ( char* ) &temp, sizeof ( Student ) );

*** while ( ! MyFile.eof() )
*** {
*** *** cout << "Name: " << temp.names << endl
*** *** *** * << "Age:* " << temp.other << endl << endl;


*** *** MyFile.read ( ( char* ) &temp, sizeof ( Student ) );
*** }

*** cout << endl << "Press any key to continue back to main menu" << endl;
*** getch();
*** clrscr();
*** mainMenu();

*** MyFile.close();
}
//------------------------------------------------------------------------------
void createFile()
{
*** if( ! MyFile )
*** {
*** *** MyFile.close();
*** *** MyFile.open(FILE_PATH, ios::binary | ios::in | ios::out);
*** }

*** if ( ! MyFile )
*** {
*** *** cout << "File Error: File does not exist. Creating new file..."
*** *** *** * << endl << "Click to continue to main menu...";
*** *** getch();
*** *** clrscr();
*** }
}

c++

3 Contributors
4 Replies
11K Views
8 Hours Discussion Span
Latest Post 12 Years Ago Latest Post by np complete

np complete 8 Newbie Poster

12 Years Ago

When you are searching in the file, use a while loop.

student User;
int flag = 0;
char studentName[16];

cout<<"\n Enter the name to be searched : ";
cin.getline(studentName, 16);

fstream file( // open the database )

 while( !file.eof() )
 {

    file.read((char*) &User,sizeof(User));

    if( strcmp (User.names, studentName) ==0 )
    {

       // found, print it
       flag = 1;
    }

  }

  if( flag == 0 )
  {
    //print not found
  }

Similarly, do the same for deleting.

Another advice, this is C++, so instead of structure, try using classes.

Reply to this topic

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.

rubberman 1,355 Nearly a Posting Virtuoso Featured Poster · Answer 1 · 2012-09-24T05:24:59+00:00

What are all those leading asterisks? Is that actually in your code, or is it just showing where tab spaces are located?

stevensonnz 0 Newbie Poster · Answer 2 · 2012-09-24T05:37:23+00:00

Thats just showing where tabs are for some reason. They are NOT in my code

stevensonnz 0 Newbie Poster · Answer 3 · 2012-09-24T08:16:54+00:00

//------------------------------------------------------------------------------

#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <conio.h>
#include <fstream>

using namespace std;

const char FILE_PATH[] = "E:\\iofile";
//------------------------------------------------------------------------------

struct Student
{
    char names [ 16 ];
    int other;
};

fstream MyFile ( FILE_PATH , ios :: binary | ios :: in | ios :: out );

void createFile();
void mainMenu();
void funcSwitch();
void addRecord();
int displayRecord();
void updateRecord();
void deleteRecord();
void printRecords();
int searchRecord();
//------------------------------------------------------------------------------
int main ( int argc, char* argv [] )
{
    createFile();

    mainMenu();
}
//------------------------------------------------------------------------------
void mainMenu()
{
    cout << "Welcome to School Enrolment System" << endl << endl
          << "Please enter your selection: " << endl
          << "1.   Register - New Student (Add record)" << endl
          << "2.   Look Up - Existing Student (Display record)" << endl
          << "3.   Change Details (Update record)" << endl
          << "4.   Remove Student (Delete record)" << endl
          << "5.   Show all Students (Print all)" << endl
          << "6.   Exit " << endl << endl
          << "Selection: ";

    funcSwitch();
}
//------------------------------------------------------------------------------
void funcSwitch()
{
   char choice;

    choice = getch();
    clrscr();
    while ( choice != 54 )
   {
      switch ( choice )
        {
         case '1' :
            addRecord();
            getch();
                clrscr();
               break;

         case '2' :
            displayRecord();
            getch();
               break;

         case '3' :
            updateRecord();
            getch();
               break;

         case '4' :
            deleteRecord();
            getch();
               break;

         case '5' :
            printRecords();
            getch();
               break;

         case '6' :
            break;

         default :
                cout << choice << " is not a vaild choice" << endl << endl
                      << "Press any key to choose again... ";
            getch();
                clrscr();

      }
      mainMenu();
        choice = getch();
        clrscr();
   }
}
//------------------------------------------------------------------------------
void addRecord()
{
    Student temp;

    cout << "Welcome new Student!" << endl
          << "We're going to set you up with a new Enrolment..." << endl
          << "All we need is a few details, let's begin: " << endl;

    cout << endl << "Please enter first name : ";
    cin >> temp.names;



    cout << endl << "Please enter your age : ";
    cin >> temp.other;


    MyFile.open ( FILE_PATH , ios :: binary | ios :: app | ios :: out );
    MyFile.clear();
    MyFile.write ( ( const char* ) &temp, sizeof ( Student ) );
    MyFile.clear();
    MyFile.close();
}
//------------------------------------------------------------------------------
int searchRecord()
{

    return 0;
}
//------------------------------------------------------------------------------
int displayRecord()
{
    Student temp;
    int age;
    int position;

    cout << "Enter age of person you are seeking: ";
    cin >> age;
    clrscr();



    MyFile.open ( FILE_PATH , ios :: binary | ios :: in );
    MyFile.clear();
    MyFile.seekp ( position * sizeof ( Student ), ios :: beg );
    MyFile.read ( ( char* ) &temp, sizeof ( Student ) );

    if ( age != temp.other )
    {
        cout << endl << "No record found. Press any key to continue...";
    }
    else
    {
        cout << "We found your record: " << endl << endl
              << "Name: " << temp.names << endl
              << "Age:  " << temp.other << endl;
    }

         cout << endl << "Press any key to continue..." << endl;
         getch();
         clrscr();
         mainMenu();
         MyFile.close();
         return 0;

}
//------------------------------------------------------------------------------
void updateRecord()
{
    Student temp;
    time_t t;
    char choice;
    int position;

    position = displayRecord ();

    MyFile.open( FILE_PATH, ios :: binary | ios :: out );
    MyFile.clear();

    if( position != -1 )
    {
        cout << endl << "Do you want to Update this Record( y or n )";
        choice = getch();
    }

    if( choice == 'y' )
    {
        cout << endl << "Enter name : ";
        cin >> temp.names;

        cout << endl << "And your age : ";
        cin >> temp.other;




        MyFile.open( FILE_PATH, ios :: binary | ios :: out );
        MyFile.clear();
        MyFile.seekp( position * sizeof( Student ), ios :: beg );
      MyFile.clear();
        MyFile.write( ( const char* ) &temp, sizeof( Student ) );
      MyFile.close();
    }
}


//------------------------------------------------------------------------------
void deleteRecord()
{

    Student temp;
    char choice;
    int position;

    -MyFile.open( FILE_PATH, ios :: binary | ios :: in | ios :: out );
    MyFile.clear();
    MyFile.seekp( position * sizeof( Student ), ios :: beg );
    MyFile.read( ( char* )&temp, sizeof( Student ) );

    cout << endl << endl;
    cout << "Would you like to delete this record? Yes (y) or No (n): ";
    cin >> choice;

    choice = getch();

    MyFile.seekp( position * sizeof( Student ), ios :: beg );
    MyFile.write( ( const char* )&temp, sizeof( Student ) );

    getch();
    clrscr();
    mainMenu();

    MyFile.close();
}

//-----------------------------------------------------------------------------

void printRecords()
{
    Student temp;

    MyFile.open ( FILE_PATH , ios :: binary | ios :: in );
    MyFile.clear();
    MyFile.read ( ( char* ) &temp, sizeof ( Student ) );

    while ( ! MyFile.eof() )
    {
        cout << "Name: " << temp.names << endl
              << "Age:  " << temp.other << endl << endl;


        MyFile.read ( ( char* ) &temp, sizeof ( Student ) );
    }

    cout << endl << "Press any key to continue back to main menu" << endl;
    getch();
    clrscr();
    mainMenu();

    MyFile.close();
}
//------------------------------------------------------------------------------
void createFile()
{
    if( ! MyFile )
    {
        MyFile.close();
        MyFile.open(FILE_PATH, ios::binary | ios::in | ios::out);
    }

    if ( ! MyFile )
    {
        cout << "File Error: File does not exist. Creating new file..."
              << endl << "Click to continue to main menu...";
        getch();
        clrscr();
    }
}
//------------------------------------------------------------------------------