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iOS Objective-C Basics (Retired) Introduction to Objective-C Inheritance

XCode Output

While following along with the instructor and executing the first build I discovered that my output is different than that shown in the video. The video shows "shape area -1.000000" but for my result I received an output on two parts of the bottom portion of my XCode display - on the left there is "L shape - (Shape *) 0x6080000004210" and on the right "(lldb) is displayed.

I double checked that I entered the same code as the video and suspect that perhaps my XCode settings may need to be adjusted. Any suggestions?

2 Answers

Stone Preston
Stone Preston
42,016 Points

youve got an uncaught exception that is being thrown. so something is wrong with your code. post the code you are using please

I meant to post the code as a comment to your response, but it looks like I posted it as a top level comment. The code is now here if you wouldn't mind giving it a quick look. Much appreciated!

Thanks Stone. Here is the main.m file:

#import <Cocoa/Cocoa.h>
#import "Shape.h"

int main()
    Shape *shape = [[Shape alloc] init];
    NSLog(@"Shape area %f", [shape area]);

    return 0;

Shape.h file:

#import <Foundation/Foundation.h>

@interface Shape : NSObject

Shape.m file:

#import "Shape.h"

@implementation Shape

-(float)area {

    return -1;


Circle.h file:

#import "Shape.h"

@interface Circle : Shape

@property(nonatomic) float radius;


Circle.m file:

#import "Circle.h"

@implementation Circle
-(float)area {
    return M_PI * self.radius * self.radius;