-(UserDetail *)functionCheck :(NSString *)str { UserDetail *d2=[[UserDetail alloc] init]; NSLog(@\"check address::::::> %p\",&d2); d2.auth_token=str
d2 is a pointer to the allocated object, so what you want is to log the value of d2, not its address &d2:
d2
&d2
NSLog(@"check address::::::> %p", d2); // remove the & !
(&d2 is the address of the local stack variable, and that may be the same for each call.)