Sorting data in files: distribution of the initial series C++

Sorting data in files: distribution of the initial series C++
Somethimes there are so many data in file to sort that PC just can't process, so you need such a algorithm as
this one. I used pyramid sorting (it's logarithm sotring).

#include "stdafx.h" 

#include "iostream" 

#include "stdio.h" 

#include <fstream> 

#include <ctime>

using namespace std;

void sift( int *array, int , int );

void generateRand(int n);

void heapsort( int *array, int );

 void main()
 {
      int i, size = 0;
      int *array;
      cout<<"Input number of elements to generate\n";
      int N;
      cin>>N;
      generateRand(N);
      //if you don't know how many elemets are in text file
      ifstream fin("file_input.txt");
      while(!fin.eof())
      {
         fin>>i;
         ++size;
      }


      fin.close();
      size--;
      cout << "Number of elements: \n ";
      cout << size<<"\n";
      array = new int[size];
      i = 0;
      ifstream fin2("file_input.txt");
      while(!fin2.eof())
      {
           fin2>>array[i];
            i++;
      }
      fin2.close();
      heapsort( array, size );
      cout<<"\nResultes are in file_out.txt\n";
 }


void sift( int *array, int L, int R )
{
   int i, j;
   int item;
   i = L;
   j = 2*L;
   item = array[L];
   if ( j < R && array[j] < array[j + 1] ) j++;
   while ( j <= R && item < array[j] )
   {
     array[i] = array[j];
     i = j;
     j = 2*j;
     if ( j < R && array[j] < array[j + 1] ) j++;
   }
   array[i] = item; 
}


void heapsort( int *array, int size )
{
   ofstream fout2("file_out.txt");
   int sort=0;
   int L, R;
   int item;
   L = size/2;
   R = size - 1;
   while ( L > 0 )
   {
     L--;
     sift( array, L, R );
     ++sort;
   }


   fout2<<array[0]<<" ";
  while ( R > 0 )
  {
     item = array[0];
     array[0] = array[R];
     array[R] = item;
     R--;
     sift( array, L, R );
     fout2<<array[L]<<" ";
     ++sort;
   }
   fout2.close();
   cout<<"\nf: "<<sort;
 }


// generating numbers in file 
void generateRand(int n)
{
   ofstream fout("file_input.txt");
   srand ( time(NULL) );
   int temp;
      for(int i = 0; i<n; i++)
   {
     temp = rand() % 200;
     fout<<temp<<" ";
   }
   fout.close();
   cout<<"Generating completed\n"; 
}