Data Structures in C – Everything you need to know

Data structures in C are used for storing data in a manner that is both orderly and accessible. C programming language consists of several data structures which include array, queue, stack, tree, and linked list, to name a few. Programmers select an apt data structure determined by the purpose or the task. 

Let us take a look at a few of the data structures:

Array

An array is a collection of elements in series, of similar kinds of data. The data are stored serially in memory. An array can also be called a data structure that has similar kinds of elements. Unlike in Java, the array elements are not treated as objects in C.

Let’s visualize it like this, you can imagine yourself in a musical instrument store. Now you are asked to arrange all the musical instruments of one brand and type at a place vertically. This sequential collection of instruments will be called an array.

There are two types of array; Single-dimensional array and Multi-dimensional array.

Stack

It is a linear data structure. The last in the first out approach is followed by the stack. A new item is added on the top of a stack. The operation for both insertion and deletion is performed from one end of the stack.

Two functions are associated with stack, which includes the push function and the pop function.

  • Push function is used for adding elements to the stack
  • Pop function is used for removing elements from the stack.

For example, imagine if you have a stack of pillows. At a time, you can put one pillow on the stack. Similarly, to remove it, you can remove one pillow at a time. When you put on one pillow, the process is called the push function; and as you remove it, the process is called the pop function.

The last placed pillow has to be moved first while removing it from the stack; therefore, the stack follows the approach of last in first out.

Queue

A queue is a linear data structure where a collection of elements is stored. This data structure operates on the First in First out (FIFO) algorithm.

For example, you visit a bank and you find a lot of customers already standing in the queue. You are asked to get a token. The token is offered so that the first come first serve approach can be maintained. As your number comes, you get called by the bank executive, or your number flashes on the screen. This is how the concept of queue works.

Linked List

A linked list in C is a linear data structure. It is almost like an array but the only difference is that the linked list is not sequentially stored in the memory. Each linked list has two sections, which include the data section and the address section. These sections hold the address of the next element in the list, called a node.

The size of the linked list is adjustable and the data items may be added at any location in the list.

Linked list comes in three types, including singly link list, doubly link list, and circular link list.

Binary Tree

It is a hierarchical data structure using C. The top most element in the Binary Tree is called the root of the tree. Every node in this data structure can have at most two children. By using index, elements can be accessed randomly. The two major advantages of Binary Tree include representation of data with some relationship, and efficient search and insertion. However, the data structure is not that flexible and the sorting can be difficult. 

The common traversal methods include:

  • Preorder (root) : print-left-right
  • Postorder (root) : left-right-print 
  • Inorder (root) : left-print-right

Binary Search Tree

A binary search tree comes with additional restrictions. The restrictions include; the left child will always be lesser than the root node; while the right child will always be greater than the root node. As compared to binary trees, search, insertion, and deletion are much more efficient in binary search trees. The data structure also maintains order in elements. It also finds the minimum and maximum nodes in the tree, very easily.

Binary search tree is ideal for sorting hierarchical data.

Hashing

This data structure is used for implementing an associative array. A hash function is used by a hash table to compute an index to an array of buckets. Hash tables are one of the important data structures.

Due to being the simplest data structure, the Array data structure is often preferred by many professionals. To understand the Data Structures in C in greater detail, you can head to the Great Learning Academy and find easy-to-understand tutorials on all such subjects.