C++ Program to cont the occurance of a word in a scentence of a file

//programe to count the occurance of the word 'do'

#include<fstream.h>
#include<conio.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
void countdo();
void main()
{  clrscr();
   countdo();
   getch();
}
void countdo()
{  char str[50], arr[10];
   int i=0;
   fstream f1("memo.txt",ios::in);
   if (!f1)
   {  cout<<"\n could not find";
      getch();
      exit(-1);
   }
   char ch;
   cout<<"\n THE SENTENCE IS : ";
   while (!f1.eof())
   {    f1.get(ch);
cout<<ch;
   }
   f1.close();
   fstream f("memo.txt",ios::in);
   while (!f.eof())
   {  f>>arr;
      if (strcmp (arr,"do")==0)
      i++;
   }
   f.close();
   cout<<"\n 'do' occured "<<i<<" times";
   return;
}