Code-Along: Parrot

Objectives

Create variables.
Call methods to manipulate strings.
Concatenate strings with methods on NSString and NSMutableString.
Print to the console with NSLog() supplied with interpolated strings.

Instructions

This code-along lab will walk you through creating, manipulating, and concatenating (combining) strings while printing them with NSLog().

Open the objc-parrot.xcodeproj file and navigate to the FISAppDelegate.m implementation file. You'll enter all of your code in the application:didFinishLaunchingWithOptions: method body before the return YES line.

Top-tip: If you wish to play around with Objective-C code snippets, this location in a blank program (or one of these early labs that we're supplying to you) is the best option for a "playground". Objective-C is not accurately supported by any REPL or by playgrounds like many other programming languages including Swift. It takes a full Xcode project to run code snippets.

Code-Along I: "Squawk!"

Print the string @"Squawk!" to the console by placing it directly inside an NSLog():

NSLog(@"Squawk!");
Run the program with ⌘``R, this will print Squawk!.

Create an NSString variable called squawk and set it equal to a string literal @"squawk" in all lowercase, then submit it to an NSLog() as format argument:

NSString *squawk = @"squawk";
NSLog(@"%@", squawk);
Run the program with ⌘``R, this will print squawk.

Now, set the squawk string variable equal to a call of the uppercaseString method on itself:

squawk = [squawk capitalizedString];

Then add an ! to squawk by setting it equal to a call of stringByAppendingString on itself:

squawk = [squawk stringByAppendingString:@"!"];

Now, print squawk to the console using NSLog():

NSLog(@"%@", squawk);
Run the program with ⌘``R, this will print Squawk!.

At the end of this code-along your console should print out:

Squawk!
squawk
Squawk!

Code-Along II: "Dead men tell no tales!"

Create three NSString variables; deadMen, tell, and noTales; and set them equal to, respectively, @"Dead men", @"tell", and @"no tales":

NSString *deadMen = @"Dead men";
NSString *tell = @"tell";
NSString *noTales = @"no tales";

Use the formatting ability of NSLog() to print these three string concatenated into a regular sentence, with a space between each format specifier and an exclamation point (!) at the end:

NSLog(@"%@ %@ %@!", deadMen, tell, noTales);
Run the program with ⌘``R, this will print Dead men tell no tales!.

Create a new NSMutableString variable called pirateParrot and set it equal to an +alloc -init of a new NSMutableString:

NSMutableString *pirateParrot = [[NSMutableString alloc] init];

Now, append deadMen to pirateParrot by calling the appendString: method on pirateParrot with deadMen supplied as the argument:

[pirateParrot appendString:deadMen];
Run the program with ⌘``R, this will print Dead men.

Then, append tell and noTales to pirateParrot by calling the appendFormat: method on pirateParrot and supplying a formatted string that includes a space before tell, a space between tell and noTales, and an exclamation point (!) at the end:

[pirateParrot appendFormat:@" %@ %@!", tell, noTales];

Now, print pirateParrot to the console using an NSLog():

NSLog(@"%@", pirateParrot);
Run the program with ⌘``R, this will print Dead men tell no tales!.

At the end of this code-along, your console should print out:

Squawk!
squawk
Squawk!
Dead men tell no tales!
Dead men tell no tales!

Code-Along III: Iago Is Molting

Create two new NSString variables called iagoLook and iagoMolting and respectively set them equal to the lowercase strings @"look at me" and @"i'm molting":

NSString *iagoLook = @"look at me";
NSString *iagoMolting = @"i'm molting";

Print a concatenation of the strings using an NSLog():

NSLog(@"%@ %@", iagoLook, iagoMolting);
Run the program with ⌘``R, this will print look at me i'm molting.

Make the strings uppercase by setting the strings equal to a call of the uppercaseString method to themselves, then NSLog() the strings again like above:

iagoLook = [iagoLook uppercaseString];
iagoMolting = [iagoMolting uppercaseString];
NSLog(@"%@ %@", iagoLook, iagoMolting);
Run the program with ⌘``R, this will print LOOK AT ME I'M MOLTING.

Create a new NSString variable called iagoShout and set it equal a call of NSString's stringWithFormat: method supplied with a format string with two object format specifiers separated by a space and ending with an ! ("exclamation point"), and the arguments iagoLook and iagoMolting, then print iagoShout using an NSLog():

NSString *iagoShout = [NSString stringWithFormat:@"%@ %@!", iagoLook, iagoMolting];
NSLog(@"%@", iagoShout);
Run the program with ⌘``R, this will print LOOK AT ME I'M MOLTING!.