var i, selectedValue, searchedValue, searchedIndex: integer;
arr:array [1..10] of integer;
isExist: boolean;

begin
  for i:=1 to 10 do
  arr[i]:=random(11)-5;

  writeln('Исходный массив');
  for i:= 1 to 10 do
          write(arr[i]:3);
  writeln;

  selectedValue := arr[4];
  searchedValue := 0;
  searchedIndex := 0;
  isExist := false;

  for i:=1 to 10 do
    begin
      if (arr[i] > 0) and (i <> 4)
      then
      begin
        searchedValue := arr[i];
        searchedIndex := i;
        isExist := true;
      end;
    end;
  if (isExist <> true)
    then
      writeln('Нет подходящего елемента') else
        begin
          arr[4] := searchedValue;
          arr[searchedIndex] := selectedValue;
        end;
      writeln('Результат');
      for i := 1 to 10 do
        write(arr[i]:3);
      writeln;
    end.