生成随机字符串

void getRandString(int len, char * randBuf)
{
	int flag = -1;
	// 设置随机种子
	srand(time(NULL));
	// 随机字符串: A-Z, a-z, 0-9, 特殊字符(!@#$%^&*()_+=)
	char chars[] = "!@#$%^&*()_+=";
	for (int i = 0; i < len - 1; ++i)
	{
		flag = rand() % 4;
		switch (flag)
		{
		case 0:
			randBuf[i] = 'Z' - rand() % 26;
			break;
		case 1:
			randBuf[i] = 'z' - rand() % 26;
			break;
		case 3:
			randBuf[i] = rand() % 10 + '0';
			break;
		case 2:
			randBuf[i] = chars[rand() % strlen(chars)];
			break;
		default:
			break;
		}
	}
	randBuf[len - 1] = '\0';
}