sort string in file txt

[amen]

can anybody give me an idea how to sort string in alphabetical order in file.text after user input string and in the file already had a list of string?
which is the best,let user input the all string first then sorting it or sorting if after user input the string?

#include <iostream.h>
#include <fstream.h>

void main()
{

	fstream kamus("Adkjektif.txt",ios::in | ios::out | ios::app);
   const size = 30;
   char kata2[size];
   cout<<"input string (end for stop)"<<endl;
   for(;;)
   {

   	cin.getline(kata2,size);
   	if (strcmpi(kata2,"end")==0)
   		break;
         else
   	 kamus<<kata2<<endl;

   }
	kamus.close();
}

this is the content of the file

small
tall
big

[Ancient Dragon]

there are methods of sorting text files, but they are generally pretty complicated. If the file is small enough, just read all the strings into an in-memory array, sort the array, then rewrite them back to the file. If you are writing c++ program that is pretty easy -- read the strings into a std::vector array, then use std::sort() to sort it.

Use a pretty recent compiler such as Dev-C++. The code you posted uses iostream.h which has been obsolete for several years, so I suspect you are using a pretty ancient compiler such as Turbo C++.