O'Reilly logo

Learning Swift by Andrew J Wagner

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Control flow

A program wouldn't be very useful if it were a single fixed list of commands that always did the same thing. With a single code path, a calculator app would only be able to perform one operation. To make an app more powerful, there are a number of ways in which we can use the data to make decisions as to what to do next.

Conditionals

The most basic way to control the flow of a program is to specify certain code that should only be executed if a certain condition is met. In Swift, we do that with an if statement. Let's look at an example:

if invitees.count > 20 {
   println("Too many people invited")
}

Semantically, the preceding code reads, "If the number of invitees is greater than 20, print Too many people invited. This example only executes ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required