how to update a string upon variable change in Swift
<p>sorry for the VERY beginner question... I am just learning to code Swift. 
I am defining a variable, then printing a conditioned message based on its value. When I change the variable to another value I would expect the message string to change, but it doesn't. What am I doing wrong?
This is the code:</p>

<pre><code>//: Playground - noun: a place where people can play

import Cocoa

var str = "Hello, playground"


var townname = "Azadinos"
var population: Int = 5422
var message: String
var Haspostoffice: Bool = true

if population &lt; 10000 {
        message = "with a population of \(population), \(townname) is a small town"
} else if population &gt;= 10000 &amp;&amp; population &lt; 15000 {
        message = "with a population of \(population), \(townname) is a medium sized town!"
}else {message = "\(townname) is a huge town!"}

print (message)

population = 250000

print (population)

print(message)
</code></pre>

<p>I would expect that the second message is different than the first one, but it isn't. What am I doing wrong?
thanks a lot</p>