Pass value by singleton

GeneralData.h

+(GeneralData *) sharedInstance;

@property (nonatomic) User *user;

GeneralData.m

static GeneralData __strong *generalDataObject = nil;

@synthesize user;

+(GeneralData *) sharedInstance
{
    static dispatch_once_t pred;
    dispatch_once(&pred, ^{
        generalDataObject = [[self alloc]init];
    });
    return generalDataObject;
}
//Singleton Reference : http://goo.gl/1KBHH

ViewController1.m

#import "GeneralData.h";
- (IBAction)passValueButton:(id)sender { //An action method
{
    User *user = [[User alloc] init];
    user.name = "Ryan";
    user.age = "26";
    [GeneralData sharedInstance].user = user;
}

ViewController2.m

#import "GeneralData.h";
- (void)viewDidLoad
{
    [super viewDidLoad];
    User *currentUser = [GeneralData sharedInstance].user;
    NSLog(@"Name : %@", currentUser.name);
    NSLog(@"Age : %@", currentUser.age);
    
}