c - Random number function is misfiring

Question

I have a very simple iPhone app that requires a random integer from 1-100.

I have a button that calls the random number function then displays it.

-(IBAction)buttonReleased;
{
    srandom(time(NULL)); 
    int theNum = random() % 100 + 1;
    numberDisplay.text = [NSString stringWithFormat:@"%d", theNum];
}

The problem is, if I press the button quickly, sometimes it won't display a new random number.

Answer 1

The problem is you're seeding with time.

time is only updated every second, so if you click it within the second, you will seed the generator with the same number, which means you'll be getting the same number.

You should only be seeding once, at the start of the application.