2 задача 5 вариант

zadan_2.pas

{модуль}

unit LinkedList;
interface
	type
		pt =^ elem;
		elem = record
			line: string;
			index: integer;
			prev: pt;
			next: pt;
		end;
	procedure put(var ll: pt; entry: string);
	function get(ll: pt; index: integer): pt;
	procedure printForward(var ll: pt);
	procedure printBack(var ll: pt);
	procedure move(var ll: pt; from: integer; upto: integer; after: integer);
implementation
	procedure put(var ll: pt; entry: string);
		var
			p, q: pt;
			counter: integer;
		begin
			new(q);
			q^.line := entry;
			q^.index := 1;
			q^.prev := nil;
			q^.next := nil;
			if ll = nil then
				ll := q
			else
				begin
					p := ll;
					counter := 1;
					while p^.next <> nil do begin
						counter := counter + 1;
						p^.next^.prev := p;
						p := p^.next;
						p^.index := counter;
					end;
					q^.prev := p;
					p^.next := q;
					q^.index := counter + 1;
				end;
		end;

	function get(ll: pt; index: integer): pt;
		begin
			while ll <> nil do begin
				if ll^.index = index then begin
					get := ll;
					break;
				end;
				if ll^.next = nil then
					get := ll;
				ll := ll^.next;
			end;
		end;

	procedure printForward(var ll: pt);
		begin
			if ll <> nil then
				begin
					writeln(ll^.index, ' ', ll^.line);
					printForward(ll^.next);
				end;
		end;

	procedure printBack(var ll: pt);
		begin
			if ll <> nil then begin
				printBack(ll^.next);
				writeln(ll^.line);
			end;
		end;

	procedure move(var ll: pt; from: integer; upto: integer; after: integer);
		var
			nb, kb, k: pt;
		begin
			nb := get(ll, from);
			kb := get(ll, upto);
			k  := get(ll, after);
			nb^.prev^.next := kb^.next;
			kb^.next := k^.next;
			k^.next := nb;
		end;
end.

{программа}

program zadan_2;
uses LinkedList;
var
	file1: textfile;
	llist: pt;
	str: string;
	nb, kb, k: integer;
begin
	assign(file1, 'inp.txt');
	reset(file1);
	repeat
		readln(file1, str);
		put(llist, str);
	until(EOF(file1));
	write('From line(_ > 1): '); read(nb);
	kb := nb-1;
	while kb < nb do begin
		write('To line(_ > ', nb, '): ');
		read(kb);
	end;
	k := nb;
	while (k >= nb) and (k <= kb) do begin
		write('After line(_ < ', nb, ' and _ > ', kb, '): ');
		read(k);
	end;
	move(llist, nb, kb, k);
	printForward(llist);
end.