diskfun.cpp

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// diskfun.cpp
// reads and writes several objects to disk
#include <fstream>                //for file streams
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class person                      //class of persons
   {
   protected:
      char name[80];              //person's name
      int age;                    //person's age
   public:
      void getData()              //get person's data
         {
         cout << "\n   Enter name: "; cin >> name;
         cout << "   Enter age: "; cin >> age;
         }
      void showData()             //display person's data
         {
         cout << "\n   Name: " << name;
         cout << "\n   Age: " << age;
         }
   };
////////////////////////////////////////////////////////////////
int main()
   {
   char ch;
   person pers;                   //create person object
   fstream file;                  //create input/output file
                                  //open for append
   file.open("GROUP.DAT", ios::app | ios::out |
                                      ios::in | ios::binary );
   do                             //data from user to file
      {
      cout << "\nEnter person's data:";
      pers.getData();             //get one person's data
                                  //write to file
      file.write( reinterpret_cast<char*>(&pers), sizeof(pers) );
      cout << "Enter another person (y/n)? ";
      cin >> ch;
      }
   while(ch=='y');                //quit on 'n'
   file.seekg(0);                 //reset to start of file
                                  //read first person
   file.read( reinterpret_cast<char*>(&pers), sizeof(pers) );
   while( !file.eof() )           //quit on EOF
      {
      cout << "\nPerson:";        //display person
      pers.showData();            //read another person
      file.read( reinterpret_cast<char*>(&pers), sizeof(pers) );  
      }
   cout << endl;
   return 0;
   }