Objective-C Pangram

NSString+Pangram.m

- (BOOL)pangram {
    NSMutableSet *set = [[NSMutableSet alloc] init];
    for (int i = 0; i < self.length; i++) {
        
        if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[self characterAtIndex:i]]) {
            
            [set addObject:[NSString stringWithFormat:@"%c", [self characterAtIndex:i]]];
            
        } else if ([[NSCharacterSet lowercaseLetterCharacterSet] characterIsMember:[self characterAtIndex:i]]) {
            
            [set addObject:[NSString stringWithFormat:@"%c", [self characterAtIndex:i]]];
            
        } else {
            
            NSLog(@"space character");
            
        }
    }
    
    if (set.count >= 26) {
        return TRUE;
    } else {
        return FALSE;
    }

}