Is there any method to sort a link list related to data C++?

No need to bother re-posting as I can tell you that the std::list class in the C++ standard library,  which is implemented using a doubly-linked list, does in fact have a sort() method which does exactly what you want - it sorts using the character values. 

This means that digits will sort before upper case letters which will in turn sort before lower case letters. Here's a quick example:

#include
#include
#include

using namespace std;

int main()
{
   list months;  
   list::iterator it;
   months.push_back("october");
   months.push_back("December");
   months.push_back("february");
   months.push_back("1st month");
   months.sort();
   cout << "After sorting, the list contains" << endl << endl;

   for(it = months.begin(); it != months.end(); it++)
   {
      cout << *it << endl;
   } 

   cout << endl; 
   return 0;
}

The output is:

After sorting, the list contains

1st month

December

february

october