I need C++ Code for single linked list
With operations as
1)insert at any position
2)delete any
3)change the data of any position
Google is your friend in this respect - there are many code samples of single linked lists out there (a search of something like "c++ singly linked list example" returns lots of examples including the operations you require).
The other option is to try a Standard Template Library (STL) which will include this functionality.
the poster is probably not allowed to use STL for homework.