Задачи на абц

uses crt;
const
   n=4;
var
a:array[1..n] of integer;
i,p:integer;
begin
clrscr;
p:=0;
for i:=1 to n do
   begin
   write('Ââåäèòå [',i,'] ÷èñëî:');
   readln(a[i]);
   if a[i]=999 then inc(p);
   end;
if p<>0 then
   for i:=1 to n do
   write(a[i],' ') else
   writeln('Ñóììà 2õ ïîñëåäíèõ=',(a[n]+a[n-1]));
end.

uses crt;
var
a,b,m:integer;
begin
clrscr;
write('Ââåäèòå À: ');
readln(a);
write('Ââåäèòå B: ');
readln(b);
repeat
clrscr;
writeln('A=',a);
writeln('B=',b);
writeln('1: Ðàçíîñòü êâàäðàòîâ A è B');
writeln('2: Ìîäóëü ðàçíîñòè A è B');
writeln('3: Íàèáîëüøåè èç ÷èñåë A è B');
writeln('4: Óòðîåííàÿ ñóììà êóáîâ A è B');
writeln('5: Exit');
write('Âûáîð îïåðàöèè: ');
readln(m);
write('Îòâåò = ');
case m of
1: writeln(sqr(a)-sqr(b));
2: writeln(abs(a-b));
3: begin
   if a>b then
   writeln(a);
   if b>a then
   writeln(b) else
   writeln('Îíè ðàâíû');
   end;
4: writeln((a*a*a+b*b*b)*3);
5: exit;
else writeln('Òàêîé êîìàíäû íåò!');
end;
write('Äëÿ ïðîäîëæåíèÿ íàæìèòå Enter..');readln;
until m=5;
end.

uses crt;
const
   n=8;
var
y:array[1..n] of integer;
x,i,sum:integer;
begin
x:=2;
sum:=0;
for i:=1 to n do
   begin
   y[i]:=sqr(x)-5*x;
   writeln(x,'^2 - 5*',x,' = ',y[i]);
   inc(x,2);
   inc(sum,y[i]);
   end;
writeln('Ñóììà âñåõ Y = ',sum);
end.