【代码笔记】iOS-产生随机字符串

一，代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    NSLog(@"---产生随机字符串---%@",[self generateTradeNO]);

}
//产生随机字符串
- (NSString *)generateTradeNO
{
    static int kNumber = 15;

    NSString *sourceStr = @"0123456789ABCDEFGHIJKLMNOPQRST";
    NSMutableString *resultStr = [[NSMutableString alloc] init];
    srand(time(0));
    for (int i = 0; i < kNumber; i++)
    {
        unsigned index = rand() % [sourceStr length];
        NSString *oneStr = [sourceStr substringWithRange:NSMakeRange(index, 1)];
        [resultStr appendString:oneStr];
    }
    return resultStr;
}

二，输出：

2015-10-23 10:04:22.908 产生随机字符串[974:46634] ---产生随机字符串---DQA5AGLNIBD52KQ