Introduction to Linked List (Complete Tutorial)
Last Updated on: 31st Dec 2025 17:44:45 PM
A Linked List is one of the most important linear data structures used in computer science and software development. It is widely used when dynamic memory usage, efficient insertion, and deletion of data are required.
In this tutorial, you will learn what a Linked List is, why it is needed, how it is stored in memory, how nodes are structured, and how it differs from arrays using simple explanations and real-life examples.
What is a Linked List?
A Linked List is a linear data structure in which elements are stored in the form of nodes.
Each node contains two parts:
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Data (the actual value)
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Link (address of the next node)
Unlike arrays, elements in a linked list are not stored in continuous memory locations. Instead, each node points to the next node, forming a chain-like structure.
Simple Definition
A linked list is a collection of nodes where each node stores data and a reference to the next node in the sequence.
Real-Life Example
Think of a treasure hunt.
Each clue contains:
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Some information (data)
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The location of the next clue (link)
You cannot jump directly to the last clue without following the chain. This is exactly how a linked list works.
Why Linked List is Needed
Arrays have several limitations that make linked lists necessary in real applications.
Problems with Arrays
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Fixed size once declared
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Insertion and deletion are costly
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Memory may get wasted if size is overestimated
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Requires continuous memory allocation
Why Linked List Solves These Problems
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Size can grow or shrink dynamically
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Efficient insertion and deletion
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Better memory utilization
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No need for continuous memory blocks
Real-Life Example
Imagine a train:
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New coaches can be added or removed easily
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Coaches do not need to be rebuilt entirely
In contrast, an array is like a row of fixed seats in a classroom, where adding or removing a seat is difficult.
Node Structure
A node is the basic building block of a linked list.
Parts of a Node
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Data Part
Stores the actual value (integer, character, object, etc.) -
Link Part
Stores the address of the next node
General Representation
Real-Life Example
Think of a WhatsApp message:
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Message text → Data
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Forward button pointing to next message → Link
Each message knows where the next one is.
Memory Representation of Linked List
In a linked list, nodes are stored at random memory locations.
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Nodes are created dynamically using heap memory
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Each node stores the address of the next node
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The first node is called the Head
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The last node points to NULL
Memory Flow Example
Real-Life Example
Consider houses in a city:
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Houses are located at different places
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Each house gives directions to the next house
This is different from apartments in a building (array), which are continuous.
Linked List vs Array (Basic Idea)
| Feature | Array | Linked List |
|---|---|---|
| Memory Allocation | Continuous | Non-continuous |
| Size | Fixed | Dynamic |
| Insertion | Slow | Fast |
| Deletion | Slow | Fast |
| Access Time | Fast (Index based) | Slow (Sequential) |
| Memory Usage | May waste memory | Efficient |
Real-Life Comparison
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Array → Cinema seats in a row
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Linked List → Passengers holding hands in a queue
Key Points to Remember
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Linked List uses dynamic memory
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Each node contains data and link
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No direct indexing is available
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Traversal is sequential
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Useful where frequent insertion and deletion are needed
Conclusion
A Linked List is a powerful and flexible data structure that overcomes many limitations of arrays. It allows dynamic memory usage and efficient data manipulation. Understanding linked lists builds a strong foundation for advanced data structures like stacks, queues, trees, and graphs.
Keep practicing — you're doing amazing!
Happy Coding! 