Difference between array and linked list always been a topic for discussion among programmers and developers. Arrays are the special type of data structure in which we are placing elements in the continuous memory location but there is a single constraint that element should be of same type whether it is integer, float, characters and so on.
Whereas Linked List data structure is the dynamic part of array data structure in which we will easily grow or shrink the memory location according to the inputs that we are receiving from the users.
What is Array Data Structure?
An array in data structure is a collection of elements that are of the same data type, where each element is uniquely accessed using its corresponding index. Elements in arrays having the same data type whether it’s integer, float and character. All elements in an array are stored in a consecutive memory location and the size of the array in data structure remains fixed during the declaration (i.e., you can’t shrink or grow array size till the execution of the program ).
Example : – 1) int arr_example [6] = { 56, 92, 38, 97, 90, 89} (Array of integers)
Here, ‘int’ keyword represents that the array is of integer type , ‘arr_example’ represents the name of an array. This array consists of all integer elements and it is of fixed size (6).
Array represents order in two forms i.e, column major order and row major order. These orders in an array are important when we go for multi-dimensional arrays to place elements like the way we represent the order of an array.
What is Linked List Data Structure?
A linked list data structure is a linear data structure in which different nodes are connected linearly with the help of pointers. In linked list data structure , we are specifically using the concept of the node. Node is generally a structure in which we divide a block into two parts one is data (value ) and another is a pointer which connects the address of the next node.
As we have represented the image below , it helps you to understand how different nodes are connected with each other in a linked list and a head pointer connects the initial node of the entire linked list and the last node of the linked list contains null so that the pointer will not points to unknown location in the memory (if the pointer points the unknown location it shows undefined behaviour).
These are basic terminologies to understand entire concept of linked list
Head : Head is a pointer that points to the first node of the linked list . If the head pointer contains NULL that indicates that the linked list is empty (there is no node in the linked list).
Next : Next pointer points to the next node of the linked list and the next pointer of the last node contains NULL to avoid undefined behaviour.
Node : Node itself is a structure that contains value and a pointer in a linked list .
Difference Between Array and Linked List
In this section we will be talking about the difference between array and linked list and we are thoroughly explain about this in the table given below.
| No. | Array | Linked List |
| 1 | Has a fixed size defined at the time of creation. | Can grow or shrink in size dynamically. |
| 2 | Elements are stored in contiguous memory locations. | Elements (nodes) are stored in non-contiguous memory. |
| 3 | Direct access to elements using index is possible. | Accessing elements requires sequential traversal. |
| 4 | Insertion and deletion are costly (due to shifting). | Insertion and deletion are easier and more efficient. |
| 5 | Memory is allocated at once. | Memory is allocated as nodes are created. |
| 6 | Searching is faster due to indexing. | Searching is slower as traversal is needed. |
| 7 | Uses less memory overall. | Requires extra memory for storing pointers. |
| 8 | Best suited when the number of elements is known. | Best suited when the number of elements changes frequently. |
| 9 | Insertion at the end is efficient (if space is available). | Insertion at the beginning or middle is efficient. |
| 10 | Inefficient memory utilization if space is unused. | Efficient memory use since memory is allocated as needed. |
| 11 | Cannot be easily resized. | Can easily expand or contract as required. |
| 12 | Difficult to implement dynamic data structures. | Ideal for implementing stacks, queues, and graphs. |
| 13 | Deleting an element requires shifting elements. | Deleting a node only requires changing a pointer. |
| 14 | No extra overhead except element storage. | Requires additional memory for pointers. |
| 15 | Can be used for multidimensional arrays (matrices). | Less convenient for matrix representations. |
| 16 | Faster access time due to CPU caching. | Slower access time due to scattered memory locations. |
| 17 | Easy to implement and understand for beginners. | Slightly more complex due to pointer manipulation. |
| 18 | Searching takes O(1) time (with index). | Searching takes O(n) time. |
| 19 | Not suitable for frequent insertion/deletion operations. | Excellent for frequent updates to data. |
| 20 | Memory waste occurs if not fully used. | Allocates memory as per requirement, reducing waste. |
Conclusion
Arrays and linked lists both serve essential roles in data structure design. Arrays provide fast access and are ideal when data size is fixed or predictable. Linked lists offer flexibility in memory allocation and are more efficient when frequent insertions and deletions are required. Understanding the difference between array and linked list that will help in selecting the right one based on the use case.
Frequently Asked Questions
What is the key difference between array and linked list in terms of memory allocation?
The key difference between array and linked list is in how they are managing memory. An array data structure always stores elements in continuous memory blocks, making them to access faster. In contrast a linked list stores each element (node) in separate memory locations and connects them using pointers, which leads to dynamic memory use in the data structure.
How does the difference between array and linked list impact insertion and deletion operations?
The difference between array and linked list always affects how we are inserting or deleting elements. Array data structure requires shifting of elements when performing insertion or deletion operations, which makes the process behaving slow. On the other hand, linked lists allow easy updates by simply changing a few pointers, saving both time and memory.
Why is access time different between array and linked list structures?
The access time differs due to the core structure. In an array, you can directly access any element using its index, which is fast and efficient. However, in a linked list, you must traverse the list node-by-node to reach your desired element. That’s one major difference between array and linked list in practical usage.
Which data structure is better for dynamic data: array or linked list?
If your application requires dynamic data handling such as frequent insertions and deletions—the linked list is usually better. This is because the difference between array and linked list becomes crucial when flexibility is required; arrays don’t resize easily, whereas linked lists can grow or shrink effortlessly.
Can you explain the difference between array and linked list using real-world examples?
Yes think of an array as a row of lockers where each locker is right next to the other, and you know the locker number. Now, imagine a linked list as a treasure map where each spot gives you the clue to the next location. This analogy highlights the fundamental difference between array and linked list which is direct access vs. sequential access.