Errors at Listing 28.7

Following along typing (and I have no clue what I’m doing in this Objective-C code since I don’t know Objective-C). I’ve just finished entering in the changes in 28.7 and now have 10 errors on the following lines:

        Contact *c1 = [[Contact alloc] initWithContactName: @"Johnny Appleseed"];
        Contact *c2 = [[Contact alloc] initWithContactName: @"Paul Bunyan"];
        Contact *c3 = [[Contact alloc] initWithContactName: @"Calamity Jane"];

Use of undeclared identifier 'Contact’
Use of undeclared identifier 'c1’
Use of undeclared identifier ‘Contact’; did you mean ‘_contacts’?
No visible @interface for ‘NSMutableArray’ declares the selector 'alloc’
Use of undeclared identifier 'Contact’
Use of undeclared identifier 'c2’
Use of undeclared identifier ‘Contact’; did you mean ‘_contacts’?
No visible @interface for ‘NSMutableArray’ declares the selector 'alloc’
Use of undeclared identifier 'Contact’
Use of undeclared identifier ‘c3’

Very odd. I quit Xcode and shut down the iMac. Went out to an appointment. Just got back, turned on the iMac, started up Xcode and reopened the project where I left off. Same errors still showing up in the project. Hit run and this time all the errors just disappeared as it was loading up the iOS Simulator. Maybe some sort of Xcode bug? I mean, I’ve seen several errors that it couldn’t load something from time to time with this iOS Simulator so maybe it was just something like that?

Same exact problem here, a year later. However, the next listing requires deleting all that stuff, so…