1. Practice utilizing the debugging suite while exercising what you've already learned.

This lab contains a few code challenges based upon manipulating strings and arrays in different ways by using loops and conditionals; it's all stuff you should already have practiced with. Now, get practice incorporating your new knowledge of debugging tools into your workflow. Use NSLog(), breakpoints, po in the console, and the variable viewer to get glimpses inside your code as it's running.

Open the *.xcworkspace file and navigate to the FISAppDelegate.h header file to declare the following methods:

• stringByRollCallingDwarfsInArray: that takes one NSArray argument called dwarfs and returns an NSString.

• arrayOfPlaneteerShoutsFromArray: that takes one NSArray argument called powers and returns an NSArray.

• summonCaptainPlanetWithPowers: that takes one NSArray argument called powers and returns an NSString.

• firstPremiumCheeseInStock:premiumCheeseNames: that takes two NSArray arguments called cheesesInStock and premiumCheeseNames, and returns an NSString.

• arrayByConvertingMoneyBagsIntoPaperBills: that takes one NSArray argument moneyBags and returns an NSArray.

Navigate to the FISAppDelegate.m implementation file and declare each method to return nil. Run the tests (⌘``U) to see that they fail. Solve each method implementation to pass the test:

1. To improve workplace safety, Doc has suggested that the seven dwarfs roll call themselves when entering or leaving the mine. Write the implementation for stringByRollCallingDwarfsInArray: to take the array of dwarf names and create a string that gives each dwarf a list number (1. to 7.), and separates each number & name with a | ("pipe"). Look at the test file to see exactly what you need to generate, but don't hard code the answer! Create the expected string programmatically by appending each dwarf's name in an interpolated string.
   Hint: When a test's "expected:" value and its "got:" value don't fit on the red highlighted line the shows up in the Code Editor when the test fails, remember that you can view the values in their entireties via the Reports navigator.

2. Let's help the Planeteers get the gusto they need to summon Captain Planet! Write the implementation of arrayOfPlaneteerShoutsFromArray: to take each of the five Planeteer's powers in the argument array and convert them into uppercase while adding an ! ("exclamation point") to the end. Return the array of altered strings. Again, don't hard code the answer. Solve this problem programmatically with loops and string interpolation!

3. Now that the Planeteers have practiced their shouts, they need to combine their powers to take pollution down to zero! Write the implementation for summonCaptainPlanetWithPowers: to take the five Planeteers' powers and combine them into the Planeteer phrase that summons Captain Planet!

   • The phrase begins with "Let our powers combine:",
   • Then each Planeteer shouts their power in sequence,
   • Then the phrase ends with "Go Planet!".
   • Each piece of the phrase should be separated by a new line (\n), and don't forget to capitalize "Planet!" as proper noun.
     Hint: You could try calling the method you just wrote inside this method implementation by calling [self arrayOfPlaneteerShoutsFromArray:powers] and capturing its return. Sending a method call to self, in this case, tells our FISAppDelegate object to call a method on itself.

4. Jerry Mouse has expensive taste in cheese and he only eats the best. Write the implementation for firstPremiumCheeseInStock:premiumCheeseNames: to compare the two argument arrays and return the first cheese in premiumCheeseNames that is also in the cheesesInStock array. If there are no cheeses common to both arrays, then the method should return @"No premium cheeses in stock." so Jerry knows to look somewhere else.

5. Scrooge McDuck is a real financial conservative and still keeps his money in dollar coins! However, he's decided to try out this new thing called "paper bills" (he hears they're the next big thing); he's brought several bags (strings) of coins to you, a bank teller, to convert into paper money. Write the implementation for arrayByConvertingMoneyBagsIntoPaperBills: to count the dollar coins (one coin is represented by one $) in each string in Scrooge's array into an equivalent paper bill (a string in the manner of @"$20"). Look at the tests to clarify the scenario, but avoid hard coding the answer!