Вопросы к экзамену с ответами и демо-программами на Паскале / ex34

{$A+,B-,D+,E+,F-,G-,I+,L+,N-,O-,P-,Q-,R-,S+,T+,V+,X+,Y+}
{$M 16384,0,655360}
program GalkaVV;
uses crt;
type
	TText=text;
	PListItem=^TListItem;
	TListItem=record
		Data:string;
		Next:PListItem;
	end;

	PFIFO=^TFIFO;
	TFIFO=object
	private
		AList,BList:PListItem;
	public
		constructor Init;
		destructor Done;
		procedure Put(Element: string);
		function Get:string;
		function NotEmpty:boolean;
	end;

constructor TFIFO.Init;
begin
	AList:=Nil;
	BList:=Nil;
end;

destructor TFIFO.Done;
var
	P:PListItem;
begin

while AList<>Nil do
	begin
		P:=AList^.Next;
		Dispose(AList);
		AList:=P;
	end;
end;


function TFIFO.Get:string;
var
	P:PListItem;
	GetData: string;
begin
	if AList=Nil then begin Get:=''; exit; end;
	P:=AList^.Next;
	GetData:=AList^.Data;
	Dispose(AList);
	AList:=P;
	if AList=nil then BList:=AList;
	Get:=GetData;
end;

Procedure TFIFO.Put(Element: string);
var
	P: PListItem;
begin
	New(P);
	P^.Data:=Element;
	if (BList=nil) and (AList=nil) then
	begin
		P^.Next:=nil;
		AList:=P;
		BList:=P;
	end
	else
	begin
		BList^.Next:=P;
		P^.Next:=nil;
		BList:=P;
	end;
end;

function TFIFO.NotEmpty;
begin
	NotEmpty:=AList<>nil;
end;


procedure Change(s1,s2:string; var AFIFO:PFIFO);
var
	Tmp:PListItem;
	p:byte;
begin
	Tmp:=AFIFO^.AList;
	while Tmp<>nil do
	begin
	p:=pos(s1,Tmp^.Data);
		while p<>0 do
		begin
			delete(Tmp^.Data,p,length(s1));
			insert(s2,Tmp^.Data,p);
			p:=pos(s1,Tmp^.Data);
		end;
		Tmp:=Tmp^.Next;
	end;
end;

var
	FiFo:PFIFO;
	Tmp:PListItem;
	str1,str2: string;
begin
	clrscr;
	New(FiFo,Init);
	str1:='g';
	str2:='BB';
	Tmp:=FiFo^.AList;
	FIFO^.put('sggasrger');
	FIFO^.put('lksjrgla');
	FIFO^.put('aoirugj');
	FIFO^.put('ksagjh8848ujh');
	Change(str1,str2,FiFo);
	while Fifo^.AList<>nil do
	begin
		writeln(FiFo^.Get);
	end;
	Dispose(FiFo,Done);
end.