LIST(1)(address)

program project1;
type
pListitem=^TListitem;
TListitem=record
info:integer;
next:pListitem;
end;
var pFirst,pTemp,pNew,pLast:pListitem;
k,key,znach,otv:integer;

Function search(key:integer):pListitem;
begin
pTemp:=pFirst^.next;
while pTemp<>nil do
begin
if (pTemp^.info=key) then
begin
result:=pTemp;
break;
end
else
begin
pTemp:=pTemp^.next;
result:=nil;
end;
end;
end;
Function search2(key:integer):pListitem;
begin
pTemp:=pFirst^.next;
pLast:=pFirst;
while (pTemp<>nil) do
if (pTemp^.info=key) then
begin
result:=pLast;
break;
end
else
begin
pTemp:=pTemp^.next;
pLast:=pLast^.next;
result:=nil;
end;
end;

Procedure AddAfter;
begin
if pFirst^.next=nil then
begin
writeln('Enter the first element:');
readln(znach);
pTemp:=pFirst;
New(pNew);
pNew^.info:=znach;
pNew^.next:=pTemp^.next;
pTemp^.next:=pNew;
end
else
begin
writeln('Enter the element after which you want to add:');
readln(key);
pTemp:=search(key);
if (pTemp<>nil) then
begin
writeln('Add the element: ');
readln(znach);
New(pNew);
pNew^.info:=znach;
pNew^.next:=pTemp^.next;
pTemp^.next:=pNew;
end
else
writeln('ERROR!!!!Element dont find');
end;
end;
Procedure AddBefore;
begin
if pFirst^.next=nil then
begin
writeln('Enter the first element:');
readln(znach);
pTemp:=pFirst;
New(pNew);
pNew^.info:=znach;
pNew^.next:=pTemp^.next;
pTemp^.next:=pNew;
end
else
begin
writeln('Enter the element before which you want to add:');
readln(key);
pTemp:=search(key);
pLast:=search2(key);
if (pTemp<>nil) then
begin
writeln('Add the element:');
readln(znach);
New(pNew);
pNew^.info:=znach;
pNew^.next:=pTemp;
pLast^.next:=pNew;
end
else
writeln('ERROR!!!!Element dont find');
end;
end;
Procedure DELETE;
begin
if pFirst^.next=nil then
writeln('List Is EMPTY.')
else
begin
writeln('Enter the element which you want delete:');
readln(key);
pTemp:=search(key);
pLast:=search2(key);
if pTemp<>nil then
begin
pLast^.next:=pTemp^.next;
pTemp:=nil;
end
else
writeln('ERROR!!!!Element dont find');
end;
end;
Procedure output;
begin
if pFirst^.next=nil then
writeln('-----List is EMPTY-----')
else
begin
pTemp:=pFirst^.next;
writeln('Content of List:');
while pTemp<>nil do
begin
write(pTemp^.info,' ');
pTemp:=pTemp^.next;
end;
end;
end;
begin
New(pFirst);
pFirst^.next:=nil;
repeat
pTemp:=pFirst^.next;
writeln(' ');
write('                                  Content of List: ');
while pTemp<>nil do
begin
write(pTemp^.info,' ');
pTemp:=pTemp^.next;
end;
writeln;
writeln('-----------MENU----------');
writeln('1-Add the element AFTER');
writeln('2-Add the element BEFORE');
writeln('3-Delete the element');
writeln('4-Output to monitor');
writeln('5-Exit');
writeln;
readln(otv);
case otv of
1:AddAfter;
2:AddBefore;
3:DELETE;
4:output;
end;
until otv=5;

end.