Why is a linked list recursive

A simple recursive function. This is a simple algorithm, and good place to start in showing the simplicity and complexity of of recursion.

Recursion allows us flexibility in printing out a list forwards or in reverse by exchanging the order of the recursive call try to write a simple printReverseList using iteration! This recursively traverses the list and adds one to every item in the list. Following are some definitely non-silly algorithms using the approach to traversing the list. This one is extremely simple, useful and not at all silly. This code is contributed by Pratham Node next;.

Recursive Python3 program to. Allocates a new node with given data. This code is contributed by sapna singh. Previous Recursive function to delete k-th node from linked list. Recommended Articles. Level order traversal with direction change after every two levels Recursive Approach. Article Contributed By :. Inside printList we have a reference to the first node of the list, but there is no variable that refers to the other nodes.

We have to use the next value from each node to get to the next node. To traverse a linked list, it is common to use a loop variable like node to refer to each of the nodes in succession. This diagram shows the nodes in the list and the values that node takes on:.

It is natural to express many list operations using recursive methods. For example, the following is a recursive algorithm for printing a list backwards: Separate the list into two pieces: the first node called the head ; and the rest called the tail. Print the tail backward. Print the head. Of course, Step 2, the recursive call, assumes that we have a way of printing a list backward. But if we assume that the recursive call works the leap of faith then we can convince ourselves that this algorithm works.

All we need are a base case and a way of proving that for any list, we will eventually get to the base case. The first line handles the base case by doing nothing. The next two lines split the list into head and tail. The last two lines print the list. The comma at the end of the last line keeps Python from printing a newline after each node. The result is a backward list. You might wonder why printList and printBackward are functions and not methods in the Node class.

The reason is that we want to use None to represent the empty list and it is not legal to invoke a method on None. This limitation makes it awkward to write list-manipulating code in a clean object-oriented style.

Can we prove that printBackward will always terminate? In other words, will it always reach the base case? How does recursion work when inserting nodes in linked lists? Ask Question. Asked 1 year, 3 months ago. Active 6 months ago. Viewed times. I have trouble understanding how these functions work:.

Improve this question. On the other hand , func is a function that you give as a parameter to process the data of each nodes. Usually it's better to give a function as parameter in the function that search your nodes , rather than hard coding it. It allows you some freedom concerning how you want to process your data in your nodes.

I have trouble understanding the purpose of the map and fold functions what are their purposes?