How to generate random uppercase characters in Objective-C

Question

How can I generate 20 Uppercase characters randomly in my Objective-C iOS app?

Answer 1

char c = (char)('A' + arc4random_uniform(25))

Will give you a random uppercase character.

Answer 2

Store ALL uppercase Characters in array,And Generate Random numbers from 0-25,using rand() or arcg4rand(),then retrieve object ay random numbered index respectively.

Answer 3

NSMutableArray *a = [[NSMutableArray alloc] initWithObjects:@"A", @"B", @"C", @"D", @"E", nil]; // You can add more uppercases here.
int firstRandom = objectAtIndex:arc4random()%[a count];
NSString *s = [[NSString alloc] initWithFormat:@"%@", [a objectAtIndex:firstRandom]];
[a removeObjectAtIndex:firstRandom];
// Avoiding some uppercase repetitions. ;-)
for (int i = 0; i < [a count]; i++) {
    int rndm = objectAtIndex:arc4random()%[a count];
    s += [a objectAtIndex:rndm];
    [a removeObjectAtIndex:rndm];
}
NSLog(@"%@", s);
[a release];
[s release];

Hope that answer this is what you want. :-)

Alberto