using System;
class UsingRecursive
{
	static void Main()
	{
		int intResult;
		string strResult;
		UsingRecursive myURec=new UsingRecursive ();
		intResult=myURec.DoFactorial (10);
		Console.WriteLine ("10的階乘是:"+intResult);
		strResult=myURec.DoStrRev ("This is a test string.");
		Console.WriteLine ("字符串反轉后為:"+"\n"+strResult);
	}
	int DoFactorial(int pF)
	{
		int result=0;
		if(pF==1)
			return 1;
		result=DoFactorial(pF-1)*pF;
		return result;
	}
	string DoStrRev(string strTest)
	{
		if(strTest.Length==1)
			return strTest;
		string strResult=strTest.Substring (strTest.Length-1,1);
		strResult+=DoStrRev(strTest.Substring (0,strTest.Length-1));
		return strResult;
	}
}