Objective-c Level-2

1 Sending a message

The real fun is accompanied by the "sending messages" began. Sending a message would be the basic building block of your objective-c apps because it's how do you tell an object to Perfor M some action or to give you some piece of information.

Sending a message requires two things-an object and a message name:

[ObjectName MessageName]; #Square brackets cannot be less

Send a simple message:

[TRYOBJC Completethischallenge];

2 Sending description information

Thetryobjcobject NSString isNSNumbersomething we made up and the objects built-in to Objective-c D NSArray, is real and has a bunch of messages you can send to them.

One of those messagesdescriptionis, and there's something extra cool about it-passing the message returns a result. Not all messages return something, but the message always returns a that represents the contents of thedescriptionNSStringobjec T that you passed the message to.

If you senddescriptiona NSString object, you'll get the characters in that string, and if you send it to a nsarray you ll Get a string containing all of the values in this array.

NSArray *foods = @[@"tacos", @"burgers"];

NSLog(@"%@", foods);

#output：
#challenge[3]: (
#    tacos,
#    burgers
#)

3 Storing the result of a message

Objective-c Level-2