what does constant property means in swift? : <p>I am learning SWIFT. I don't understand one sentence while reading book. What does the sentence below means?: </p>

<blockquote>
  <p>“Add a constant property called elementList to ViewController.swift
  and initialize it with the following element names: let elementList =
  ["Carbon", "Gold", "Chlorine", "Sodium"]”
  does it mean create new class or I have to create struct? </p>
</blockquote>
