C++ menu driven program to display the reversed scentence or count the number of scentence using files concept

#include<fstream.h>
#include<conio.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
void countline();
void main()
{  clrscr();
   int ch;
   cout<<"\n 1. wants to show the reversed file";
   cout<<"\n 2. wants to know the number of lines";
   cout<<"\n enter the choice ";
   cin>>ch;
   switch(ch)
   {case 1 :
     char str[100];
       fstream f1("mydata.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();
       char c;
       int i=0;
       fstream f("mydata.txt",ios::in);
       while (!f.eof())
       {    f.get(c);
   str[i]=c;
   i++;
       }
       str[i]='\0';
       cout<<"\n THE REVERSED SENTENCE IS :";
       for ( i=0; str[i]!='\0'; i++);
       for (int j=i-1; j>=0; j--)
       cout<<str[j];
       break;

   case 2:
     countline();

   break;
 }
   getch();
}
void countline()
{  char c;
   fstream f1("mydata.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("mydata.txt",ios::in);
   int i=0;
   while (!f.eof())
   {  f.get(c);
      if (c=='.' || c=='!' || c=='?')
      i++;
   }
   f.close();
   cout<<"\n number of line are : "<<i;
   return;
}