﻿ C Program: Convert a Doubly Linked list into a array

# C Exercises: Convert a Doubly Linked list into a array

## C Doubly Linked List : Exercise-22 with Solution

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 :

C Programming Code Editor:

What is the difficulty level of this exercise?

﻿