/swift-conjunction-function-ios-0616

Primary LanguageSwiftOtherNOASSERTION

Swift — Conjunction Function

What's Your Junction?

Objectives

  1. Use control flow statements within a function to program dynamic behavior based upon varying input arguments.

Introduction

Listen to Conjunction Junction by Schoolhouse Rock!, performed by Jack Sheldon, Terry Morel, and Mary Sue Berry in 1973.

Using a Typed Collection as an Argument

This lab requires that you type a function's argument as an array containing strings. The syntax for this is to wrap the name of the type to be held in the array with square brackets [ ]. So to type an argument as an array of type String, it would be written as [String]. Upcoming lessons will discuss types and typed collections in more detail.

Instructions

Open swift-conjunction-function.xcworkspace and navigate to the Sandbox.swift file.

Write a function named listWithElements(_:conjunction:) that takes two arguments, an array of strings named elements and a string named conjunction, and returns a string. The returned string should contain the strings from the elements array but organized into a list phrase using the conjunction argument. This means that:

  1. If the elements argument is empty, the function should return an empty string.
  2. A single string in the elements array should result to just that same string, as in "one".
  3. Two strings in the elements array should be joined with the conjunction argument, as in "one and two".
  4. Three or more strings in the elements array should be joined with commas (,), with the conjunction also joining the last element in the list phrase, as in "one, two, or three".
    Hint: Consider using a switch statement to detect these different cases.
  5. Acceptable conjunction arguments are "and", "or", and "&" ("ampersand", a symbol meaning "and"). If the conjunction argument does not match one of these three strings, the function should return a string message that reads "unknown conjunction".

If you wish to test your function with your own sample data, call it from the AppDelegate. When the tests in SandboxSpec.swift all pass you have completed this lab. View this lesson on Learn.co