NSKeyedArchiver and description method : app crashes - objective-c

Question

i tried to test NSKeyedArchiver, but my code seems to be wrong. I then tried only with a NSLog, but the NSLog returns (null) if i alloc-init my var "model" in the init method (in the controller), and it makes the app crash if i put it in viewDidLoad.
Can someone have a look and tell me if something is wrong?
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#class Model;
#interface AAViewController : UIViewController {
Model *model;
}
#property (nonatomic, retain) Model *model;
//+(BOOL)archiveRootObject:(id)rootObject toFile:(NSString *)path;
#end
______
#import "AAViewController.h"
#import "Model.h"
#implementation AAViewController
#synthesize model;
- (id) init {
self = [super init];
if (self) {
model = [[Model alloc] initWithName:#"thomas" age:13];
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
//self.model = [[Model alloc] initWithName:#"thomas" age:13];
NSLog (#"%#", self.model);
/*
if (![NSKeyedArchiver archiveRootObject:model toFile:#"test.archive"]){
NSLog (#"erreur");
[model release];
}
*/
NSLog(#"success !");
}
- (void)viewDidUnload {
//model = nil;
}
- (void)dealloc {
[model release];
[super dealloc];
}
#end
______
#import <Foundation/Foundation.h>
//#interface Model : NSObject <NSCoding>
#interface Model : NSObject {
NSString *name;
int age;
}
#property (nonatomic, copy) NSString *name;
#property (nonatomic) int age;
- (id) initWithName:(NSString *)theName age:(int)theAge;
/*
- (id) initWithCoder:(NSCoder *)encoder;
- (void) encodeWithCoder:(NSCoder *)decoder;
*/
#end
______
#import "Model.h"
#implementation Model
#synthesize name, age;
- (id) initWithName:(NSString *)theName age:(int)theAge {
self = [super init];
if (self) {
name = [theName copy];
age = theAge;
}
return self;
}
- (void) dealloc {
[name release];
[super dealloc];
}
/*
- (id) initWithCoder:(NSCoder *)decoder{
self = [super init];
if (self) {
name = [[decoder decodeObjectForKey:#"nom"] retain];
age = [decoder decodeIntForKey:#"age"];
}
return self;
}
- (void) encodeWithCoder:(NSCoder *)encoder
{
[encoder encodeObject:name forKey:#"nom"];
[encoder encodeInt:age forKey:#"age"];
}
*/
- (NSString *) description {
return [NSString stringWithFormat:#"the name is : %#, %# years old", name, age];
}
#end

Answer 1

Your app is crashing because this line is wrong:
return [NSString stringWithFormat:#"the name is : %#, %# years old", name, age];
age is an int, not an object pointer. Needs to be:
return [NSString stringWithFormat:#"the name is : %#, %d years old", name, age];
I don't think there's anything obviously wrong with your encode/decode code.