It prints da line

println("your mom is great!")

println is used to print a line of text followed by a new line character. The important thing to remember is that to add an expression to a print statment, the \( expression ) must be used.
println is essentially the equivalent to Objective-C's "NSLog".

var a = "really great!"
println("Your mom is \(a)")
// prints "Your mom is really great!"