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Ivan Kazakov
Courses Plus Student 43,317 Pointsshape description returns some hexadecimal value instead of description
I had been working out the topic using empty Objective C program template. I've added Shape header and implementation files provided as part of the Project Files download; imported Shape.h into the main.m, to be able to use Shape instance as a member of the NSArray, but yet its 'description' returns hexadecimal value instead of description.
Running complete downloaded project works just fine. I've compared all the files line by line but still can't figure out what am I missing.
3 Answers
Stone Preston
42,016 PointsI used your code and it worked fine. maybe try cleaning your build by pressing command + shift + k. not sure why its not using that overridden method.
Stone Preston
42,016 Pointscan you post the code you are using please
Ivan Kazakov
Courses Plus Student 43,317 Pointsimport <Cocoa/Cocoa.h>
import "Shape.h"
int main() { Shape *shape = [[Shape alloc] init];
NSArray *mixed = @[@23, @"tango", shape];
for(id thing in mixed)
{
NSLog(@"%@", [thing description]);
}
return 0;
}
and here is the output:
2014-07-12 20:40:31.945 MyFirstObjectiveCProgram[2416:303] 23
2014-07-12 20:40:31.947 MyFirstObjectiveCProgram[2416:303] tango
2014-07-12 20:40:31.948 MyFirstObjectiveCProgram[2416:303] <Shape: 0x608000011030>
Stone Preston
42,016 Pointsdid you override the description method in your shape implementation file? if not then thats the normal behavior of the description method inherited by NSObject. if you want it to return a different description then you will need to override that method in your Shape implementation file
Ivan Kazakov
Courses Plus Student 43,317 PointsThe Shape.m does contain the custom implementation of description method:
-(NSString *)description {
return [NSString stringWithFormat:@"I am %@. My parent is %@. area %f.",
[self class], [self superclass], [self area]];
}
That's what confuses me.
Stone Preston
42,016 Pointscan you post all the code you have. it may have something to do with how you instantiated your shape object
Ivan Kazakov
Courses Plus Student 43,317 PointsHere is all the code.
Shape.h:
```#import <Foundation/Foundation.h> @interface Shape : NSObject @property(nonatomic, copy) NSString *color;
- (double)area;
- (BOOL)hitTestAtLocation:(CGPoint)location; @end```
======================
Shape.m:
```#import "Shape.h" @implementation Shape
@synthesize color = _color;
- (double)area { return -1; }
-(BOOL)hitTestAtLocation:(CGPoint)location { return NO; }
-(NSString *)description { return [NSString stringWithFormat:@"I am %@. My parent is %@. area %f.", [self class], [self superclass], [self area]]; }
@end```
======================
main.m:
```#import <Cocoa/Cocoa.h>
import "Shape.h"
int main() { Shape *shape = [[Shape alloc] init];
NSArray *mixed = @[ @23, @"tango", shape];
for (id thing in mixed) {
NSLog(@"%@", [thing description]);
}
return 0;
}```
Ivan Kazakov
Courses Plus Student 43,317 PointsIvan Kazakov
Courses Plus Student 43,317 PointsHey, cleaning the build was helpful, thank you!