objective c - TableView with checkmarks -

I want to create a TableView with a checkmark to select one day on alarmatents. I got a code on the internet but it is not working. And I have a code from a book, but I do not even work please help me

You will have to check this way and the checkmark will be highlighted for the selected day. Enter it in cellForRowAtIndexPath

  if ([day EqualToString: selectedDay])  

{

  cell.accessoryType = UITableViewCellAccessoryCheckmark;  

}