what is diff bw throw ex; and throw;

catch(Exception ex)
{
throw;
}

It means the exception is thrown to fuction from where it is called .for example suppose you have function xyz() and in this xyz() you write "throw;" ,now u are calling xyz() function in Main() function, if there is exception then xyz() function will throw the exception to the main function.

but if you write like this

catch(Exception ex)
{
throw ex;
}

then it will terminate you program.If we talk about the above scenario then the exception will thrown to the main function by XYZ().