program BubbleSort;
uses crt;
const cls_size=50;
var name : array[1..cls_size] of string;
    phone : array[1..cls_size] of integer;
    i, nstudent, pass : integer;
    classfile : text;
    class : string[2];
    sorted : Boolean;

procedure swap( var   first , second : string ); 
var temp : string;
begin
  Temp := first;
  first := second;
  second := Temp;
end;




begin { Main Program }
   clrscr;
   write('Class :');
   readln(class);
   writeln;
   writeln('Telephone Directory in alphabetic order');
   writeln('=======================================');
   writeln;
   assign(classfile, class+'phone.dat');
   reset(classfile);
   nstudent:=0;
   while (not eof(classfile)) do
     begin
       nstudent:=nstudent+1;
       readln(classfile, name[nstudent]);
       readln(classfile, phone[nstudent]);      
     end;
   close(classfile);
   sorted:=false;
   pass:=1;
     while (pass<nstudent) and (not sorted) do
       begin
         sorted:=true;
         writeln ('Pass ', Pass);
         for i := 1 to (nstudent-Pass) do
            begin
               if name[I] > name[I+1] then
                  begin
                     sorted:=false;
                     swap(name[i], name[i+1]);
                     swap(phone[i], phone[i+1]);
                  end;  
            end;
        pass:=pass+1;
      end; 
   writeln;
   assgin(classfile,class+'phone.dat');
   rewrite(classfile);
   for i:=1 to nstudent do
      begin
        writeln('       ',name[i]:(25-length(name[i])), phone[i] );
        writeln(classfile, name[i]);
        writeln(classfile, phone[i]);
      end;
   close(classfile);
end. { Main Program }