iOS OC生成验证码

//kCharCount 生成验证码个数

- (NSString *)getAuthcode:(NSInteger)kCharCount {

    //字符串素材
   NSArray *dataArray = [[NSArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
    
    NSMutableString *authCodeStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
    //随机从数组中选取需要个数的字符串，拼接为验证码字符串
    for (int i = 0; i < kCharCount; i++) {
        NSInteger index = arc4random() % (dataArray.count-1);
        NSString *tempStr = [dataArray objectAtIndex:index];
        authCodeStr = (NSMutableString *)[authCodeStr stringByAppendingString:tempStr];
    }
    return authCodeStr;
}