iOS生成一个8位的随机密码

-(NSString *)randomPassword{

    //自动生成8位随机密码

    NSTimeInterval random=[NSDate timeIntervalSinceReferenceDate];

    NSLog(@"now:%.8f",random);

    NSString *randomString = [NSString stringWithFormat:@"%.8f",random];

    NSString *randompassword = [[randomString componentsSeparatedByString:@"."]objectAtIndex:1];

    NSLog(@"randompassword:%@",randompassword);

    return randompassword;

}