program Dekio;
const
n = 10;
var
arr: array [1 .. n] of integer;
i, l, k: integer;
begin
writeln('Введите ', n, ' элементов массива');
for i := 1 to n do
readln(arr[i]);
repeat
writeln('Введите l,k');
readln(l, k);
until (l >= 1) and (l <= n) and (k >= 1) and (k <= n);
writeln('Исходный массив');
for i := 1 to n do
write(arr[i]:4);
i := arr[l];
arr[l] := arr[k];
arr[k] := i;
writeln;
writeln('Результат');
for i := 1 to n do
write(arr[i]:4);
end.