description method is not getting called

Question

I created example to learn some basics in objective-c. I have a class called Person as shown below. in the main method I try to call description method to print some data, and AFAIK, description method is similar to toString in java..but description method I created is not called

please have a look at the code below and let me know why the contents of description method is not called.

person.h

#import <Foundation/Foundation.h>

@interface Person : NSObject {
    int age;
    int weight;
}

-(void) setAge:(int) age;
-(void) setWeight: (int) weight;

-(int) getAge;
-(int) getWeight;

-(NSString *) description;

@end

person.m

#import "Person.h"

@implementation Person

-(void) setAge:(int) a {
    age = a;
}

-(void) setWeight:(int) w {
    weight  = w;
}

-(int) getAge {
    return age;
}

-(int) getWeight {
    return weight;
}

-(NSString *) description {
    NSString *desc = @("my age is: %i and my weight is: %i", age, weight);
    NSLog(@"%@", desc);
    return desc;
}
@end

main :

#import <UIKit/UIKit.h>
#import "AppDelegate.h"
#import "Person.h"

int main(int argc, char * argv[]) {
    @autoreleasepool {

        Person *me = [[Person alloc] init];

        [me setAge:20];
        [me setWeight:55];

        NSString *desc = [me description];
        NSLog(@"%@", desc);

        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}

Answer 1

You might have the call to description method, but you aren't getting the log message. Problem is in the NSString that you produced. This is not valid:

NSString *desc = @("my age is: %i and my weight is: %i", age, weight);

Try changing this to:

NSString *desc = [NSString stringWithFormat:@"my age is: %i and my weight is: %i", age, weight];