Question

I have used rand(). But it gives a specific value even after I restart application.

I have implemented following in my application.

- (void)viewDidLoad {
[super viewDidLoad];
int x,y;

x=random() % 480; y=random() % 300;

lblT.center=CGPointMake(x,y); // my label lblT
}

Try to implement in your application, and launch application.
After restarting application, you will find that label will be on specific value.

Answer 1

arc4random() is a built-in function that does not require seeding (and so therefore does not produce predictable sequences that can be generated by using a seed), and it conveniently returns integers. I never use anything else.