C Exercises: Convert a Doubly Linked list into a array

Last update on August 02 2025 12:55:39 (UTC/GMT +8 hours)

22. Doubly Linked List to Array Conversion

Write a C program to convert a doubly linked list into an array and return it.

Sample Solution:

C Code:

#include<stdio.h>
#include <stdlib.h>
#include <string.h>

// Structure to define a doubly linked list node
struct node {
  int num;
  struct node *preptr;
  struct node *nextptr;
} *stnode, *ennode;

// Function prototypes
void DlListcreation(int n);
void display_DlList_str();
void DlList_array(int n);

int main() {
  int n, num1, a, insPlc;
  stnode = NULL;
  ennode = NULL;

  printf(" Input the number of nodes: ");
  scanf("%d", &n);

  // Function call to create a doubly linked list
  DlListcreation(n);

  // Function calls to display the doubly linked list as string and array
  display_DlList_str();
  DlList_array(n);
}

// Function to create a doubly linked list
void DlListcreation(int n) {
  int i, num;
  struct node *fnNode;

  if (n >= 1) {
    stnode = (struct node *) malloc(sizeof(struct node));
    if (stnode != NULL) {
      printf(" Input data for node 1 : "); // Assigning data in the first node
      scanf("%d", &num);
      stnode->num = num;
      stnode->preptr = NULL;
      stnode->nextptr = NULL;
      ennode = stnode;

      // Loop to create subsequent nodes and link them in the list
      for (i = 2; i <= n; i++) {
        fnNode = (struct node *) malloc(sizeof(struct node));
        if (fnNode != NULL) {
          printf(" Input data for node %d : ", i);
          scanf("%d", &num);
          fnNode->num = num;
          fnNode->preptr = ennode;
          fnNode->nextptr = NULL;
          ennode->nextptr = fnNode;
          ennode = fnNode;
        } else {
          printf(" Memory can not be allocated.");
          break;
        }
      }
    } else {
      printf(" Memory can not be allocated.");
    }
  }
}

// Function to display the doubly linked list as a string
void display_DlList_str() {
  struct node *current;
  current = stnode;
  char text_str[100] = "";

  // Loop through the list and concatenate node data to a string
  while (current != NULL) {
    char str[10];
    sprintf(str, "%d", current->num);
    strcat(text_str, str);
    strcat(text_str, " ");
    current = current->nextptr;
  }

  // Display the doubly linked list in string format
  printf("\nThe doubly linked list in string format: %s\n", text_str);
}

// Function to convert the doubly linked list to an array
void DlList_array(int n) {
  int arr[n];
  struct node *temp = stnode;
  int i;

  // Loop to store node data in an array
  for (i = 0; i < n; i++) {
    arr[i] = temp->num;
    temp = temp->nextptr;
  }

  // Display the doubly linked list in array format
  printf("\nDoubly linked list in array format:\n");
  for (i = 0; i < n; i++)
    printf("%d ", arr[i]);
}

Sample Output:

 Input the number of nodes: 4
 Input data for node 1 : 10
 Input data for node 2 : 11
 Input data for node 3 : 12
 Input data for node 4 : 13

Doubly linked list in array format:
10 11 12 13

Flowchart :

For more Practice: Solve these Related Problems:

Write a C program to convert a doubly linked list into a dynamically allocated array and print its elements.
Write a C program to convert a doubly linked list into an array and then sort the array using quicksort.
Write a C program to convert a doubly linked list into an array and calculate the sum of all its elements.
Write a C program to recursively convert a doubly linked list into an array and search for a specific element within it.

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