at writing program with java( for example program name:Digital Roots)what name shoud i get my public class ???

Azin said:

at writing program with java( for example program name:Digital Roots)what name shoud i get my public class ???

You should have exactly one public class named Main.

There is sample code for the first problem here: http://sharecode.ir/discussion/problemset/topic/175

thank you very much Amir