why NSNumber didn't show correct number
Sorry,my company mac is English version,so I have to speak English in CSDN even though I'm Chinese.
Here is my code.

A.h

#import <Cocoa/Cocoa.h>


@interface A : NSObject {
NSNumber* i;

}
@property (retain) NSNumber* i;

@end

#import "A.h"


@implementation A
@synthesize i;

-(void)dealloc{
[i release];
[super dealloc];
}

#import <Foundation/Foundation.h>
#import "A.h"

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

A *a=[[A alloc] init];

NSNumber* i=[[NSNumber alloc] initWithInt:123];

[a setI:i];

    NSLog(@"i is %d",[a i]);
    [pool drain];
    return 0;
}

I expected "i is 123" in console,but I only got "i is 109952".Why


[解决办法]
[a i]返回的是NSNumber指针，你用%d输出的是当然是整型的指针。
对于所有的NSObject对象，都用%@输出：
NSLog(@"i is %@",[a i]);
或者你想用%d，那就将对用值转成int类型：
NSLog(@"i is %d",[a i].intValue);
[解决办法]
2楼正解，或者你可以使用NSLog(@"i is %d",(int)[[a i] value]);