C Program to reverse each node value in Singly Linked List

A linked list is a linear collection of data elements, in which each node points to the next node. Unlike an array, it doesn’t have upper limit and hence extremely useful.

The task is to access value of each node of linked list and reverse them.

**Examples:**

Input : 56 87 12 49 35 Output :65 78 21 94 53 Input : 128 87 12433 491 33 Output :821 78 33421 194 33

**Algorithm:**

The task can be accomplished as:

- Linearly traverse each node of the singly linked list.
- Reverse the value of each node.
- Store the reversed value in the current node.

`// C program to reverse every node data in ` `// singly linked list. ` `#include <stdio.h> ` `#include <stdlib.h> ` ` ` `// A linked list node ` `struct` `Node { ` ` ` `int` `data; ` ` ` `struct` `Node* next; ` `}; ` ` ` `// newNode function inserts the new node at ` `// the right side of linked list ` `struct` `Node* newNode(` `int` `key) ` `{ ` ` ` `struct` `Node* temp = ` `new` `Node; ` ` ` `temp->data = key; ` ` ` `temp->next = NULL; ` ` ` `return` `temp; ` `} ` ` ` `// reverse() will receive individual data item ` `// from reverseIndividualData() and will return ` `// the reversed number to calling function ` `int` `reverse(` `int` `number) ` `{ ` ` ` `int` `new_num = 0, rem; ` ` ` ` ` `while` `(number != 0) { ` ` ` `rem = number % 10; ` ` ` `new_num = new_num * 10 + rem; ` ` ` `number = number / 10; ` ` ` `} ` ` ` ` ` `return` `new_num; ` `} ` ` ` `void` `reverseIndividualData(` `struct` `Node* node) ` `{ ` ` ` ` ` `if` `(node == NULL) ` ` ` `return` `; ` ` ` ` ` `while` `(node != NULL) { ` ` ` ` ` `/* function call to reverse(), ` ` ` `reverseIndividualData(struct Node *node) ` ` ` `will send the one data item at a time to ` ` ` `reverse(node->data) function which will ` ` ` `return updated value to node->data*/` ` ` ` ` `node->data = reverse(node->data); ` ` ` ` ` `/* updating node pointer so as to get ` ` ` `next value */` ` ` ` ` `node = node->next; ` ` ` `} ` `} ` ` ` `// Function to print nodes in linked list ` `void` `printList(` `struct` `Node* node) ` `{ ` ` ` `while` `(node != NULL) { ` ` ` `printf` `(` `"%d "` `, node->data); ` ` ` `node = node->next; ` ` ` `} ` `} ` ` ` `// Driver program to test above functions ` `int` `main() ` `{ ` ` ` `struct` `Node* head = NULL; ` ` ` `head = newNode(56); ` ` ` `head->next = newNode(87); ` ` ` `head->next->next = newNode(12); ` ` ` `head->next->next->next = newNode(49); ` ` ` `head->next->next->next->next = newNode(35); ` ` ` ` ` `printf` `(` `"\nList before reversing individual data item \n"` `); ` ` ` `printList(head); ` ` ` ` ` `reverseIndividualData(head); ` ` ` ` ` `printf` `(` `"\nList after reversing individual data item\n"` `); ` ` ` `printList(head); ` ` ` ` ` `return` `0; ` `} ` |

**Output:**

List before reversing individual data item 56 87 12 49 35 List after reversing individual data item 65 78 21 94 53

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