(NSString *)description

Objective-C Programming (2nd Edition)
1

I am running Xcode 9.0.
When I use this line of code in Chapter 21

  • (NSString *)description
    I get an error message telling me "Use of undeclared identifier ‘description’"
    I cannot figure out what this error message is telling me or how to fix it…
    Thanks for the help!
2

Please provide more information by posting enough code to make it easier to diagnose the problem.

If you paste your code between a pair of 3 back-tick characters like this:

```
Paste Your Code Here
```

It will be displayed nicely. For example:

//
//  Foo.h
//  ObjectiveCMatters
//
//  Created by Pretty Function on 7/10/17.
//  Copyright © 2017 examples. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Foo : NSObject  {
}

@property (readonly) NSString * description;

@end

//
//  Foo.m
//  ObjectiveCMatters
//
//  Created by Pretty Function on 7/10/17.
//  Copyright © 2017 examples. All rights reserved.
//

#import "Foo.h"

@implementation Foo

- (NSString *)description {
    NSLog (@"%s", __func__);
    return @"Foo...";
}

@end

//
//  main.m
//  ObjectiveCMatters
//
//  Created by Pretty Function on 7/10/17.
//  Copyright © 2017 examples. All rights reserved.
//

#import "Foo.h"

int main (int argc, const char * argv[]) {
    @autoreleasepool {
        Foo * foo = [Foo new];
        NSLog (@"%@ %@", foo, foo.description);
    }
    return 0;
}
3

Thanks. Here is the code…
\\

#import “BNREmployee.h”
#import “BNRAsset.h”

@implementation BNREmployee

//Accessor for assets properties
-(void)setAssets:(NSArray *)a
{
_assets = [a mutableCopy];
}

  • (NSArray *)assets{
    return [_assets copy];
    }

  • (void)addAsset:(BNRAsset *)a
    {
    //Is asset nil?
    if (!_assets) {

      //Create the array
  _assets = [[NSMutableArray alloc]init];

    }
    [_assets addObject:a];
    }

  • (unsigned int)valueOfAssets
    {
    //Sum up the resale value of the assets
    unsigned int sum = 0;
    for (BNRAsset *a in _assets){
    sum += [a resaleValue];
    }
    return sum;

    }

  • (double)yearsOfEmployment
    {
    //Do I have a non-nil hire date?
    if (self.hireDate){
    //NSTimeInterval; is the same as double
    NSDate *now = [NSDate date];
    NSTimeInterval secs = [now timeIntervalSinceDate:self.hireDate];
    return secs / 31557600.0; //Seconds per year
    } else{
    return 0;
    }
    }

  • (float)bodyMassIndex
    {
    float normalBMI = [super bodyMassIndex];
    return normalBMI * 0.9;

    • (NSString *)description
      {
      return [NSString stringwithformat:@"<Employee %u: $%u in assets>", self.employeeID, self.valueOfAssets];
      }

    • (void)dealloc
      {
      NSLog(@“deallocating %@”, self);
      }

}

@end

\\

4

You are missing a closing } after the line

return normalBMI * 0.9;

This is causing the compiler to include the new function (NSString *)description… as part of the bodyMasIndex function declaration and it doesn’t know what to do with it.

5

As BrianL3D1 diagnosed, you have a syntax error.

As an aside, the code posted is still in a state of jumble :slight_smile: because instead of a pair of three back-tick characters (```), a pair of two back-slash characters (\\) were used.

When you ask for help next time, please place your code between a pair of three back-tick characters like this:

```
Place code here…
```

If you are using an Apple keyboard, you will find the back-tick character (`) on the same key for the tilde character (~).

Finally, coding requires paying undivided attention to details, no matter how tiny they are.