请问这几行代码的意思是什么？

[zengzhimin1980]

private static string DecodeTime(string timeStr)
{
char[] timeArr = timeStr.ToCharArray();
timeArr[0] = (char)(timeArr[0] - '\x0002');
timeArr[1] = (char)(timeArr[1] - '\x0006');
timeArr[2] = (char)(timeArr[2] - '\x0004');
timeArr[3] = timeArr[3];
timeArr[4] = (char)(timeArr[4] - '\x0005');
timeArr[5] = timeArr[5];
timeArr[6] = (char)(timeArr[6] - '\x0003');
timeArr[7] = timeArr[7];

}

我在调试中把20090728 传入，得出的timeArr为 0*,9+7/8 为什么会这样

[Hide1984]

20090728在经过

char[] timeArr = timeStr.ToCharArray(); 
变成char[] {'2','0','0','9',...}

下面开始分析：

timeArr[0] - '\x0002'
查看ASCII码表：timeArr[0] = '2' ==> ASCII 字符'2',代码50.
timeArr[0] - '\x0002' = 50 - 2 = 代码48 ==> ASCII字符'0'.

下面同理～