Regarding the wrong output

#1
#2

Your Approach is NOT correct

we you want to make a new list then don’t do like this
you have to create complete new node
otherwise links in original list will affected

dry run this code , you will understand better

2 Approaches to solve this ques

  1. make completely new(means create new nodes) linked list , odd and even list
    OR
  2. use partition approach
    Partition Approach
    https://ide.codingblocks.com/s/573212