【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