Program to add one to a number represented by Linked List
1 --> 2 --> 3 --> 4 --> 5 --> 6 --> 7 --> 8
Number after adding one is :
1 --> 2 --> 3 --> 4 --> 5 --> 6 --> 7 --> 9

Program to add one to a number represented by Linked List
9 --> 9 --> 9 --> 9 --> 9 --> 9 --> 9 --> 9
Number after adding one is :
1 --> 0 --> 0 --> 0 --> 0 --> 0 --> 0 --> 0 --> 0