Both of these are terms used in the data structure. But there is a significant difference between stack and array. In this article, we will discuss the same. But before we do that, let us first know what a data structure is.
What is a Data Structure?
A data structure refers to the way in which the data gets organized and stored in a particular format. Data structures are required in systems so that one can access the information efficiently while still keeping the overall system intact.
In simple words, a data structure provides a logical representation of storing data in a way that we can perform various operations on that data set. This data can be stored in multiple ways, but the most common of them are stack and array. We can implement a stack of data using arrays, so they perform somewhat a similar function. But there is a major difference between them in terms of how they access data.
Let us discuss the main difference between stack and array. But we will first understand a bit more about each of these.
What is a Stack?
It is a linear data structure that appears like a list. A stack appears like a sequential collection of constituting elements. All the elements are added on top of one another like a pile of books. We can only add a new item or remove the existing ones from the top due to the stack’s sequential appearance.
We can perform two operations on a stack of data, namely, push and pop. The push operation here refers to the process of inserting an item into a stack, while the pop operation refers to the process in which we remove the existing item from a stack.
Since the item that we added recently can be removed first and the first item that we added in the stack can be removed only at the last, this data structure follows the LIFO principle (Last In First Out). Thus, we can change the size of a stack at its run time, making it a very dynamic data structure.
What is an Array?
It is also a linear data structure that consists of a collection of various elements that have the same data type. An array’s size is pre-decided. It stores all the values at a location known as the index of values.
An array is static in nature, not at all dynamic. It is because the allocation of memory happens at the compile-time itself, and it remains fixed throughout the running of the program. Thus, arrays are very efficient in storing multiple elements that belong to similar data types.
Arrays store various values of a similar type. One can access these values via the value indices. The array will provide them with random access for all the linear stored elements so that you can access them via the index.
Difference between Stack and Array
Let us talk about the differences between Stack and Array.
| Parameters | Stack | Array |
| Basics | Stack data structures are abstract in nature. The data types get arranged in a linear format that looks like a pile. | Array data structures are not abstract. The constituent elements are of the same data type, and they get arranged in a linear format. |
| Accessing of Data | We can only access the currently entered data first. The element that was added in a stack can be accessed only at the last. Thus, it follows the LIFO principle (Last In, First Out). | We can identify the elements via the value index. This way, we can access any element at any given time. The first index of an array is always available at the 0 index. |
| Data Types | The elements of a stack need not be of the same data types. | The constituent elements of an array must always be of the same data types. |
| Range of Data Access | Due to LIFO, we have limited access to the elements in a stack. At any given point, we can only access the currently entered data/element. | The array comes with random access to data. It means that we can perform the read or write operations on any element present at any position via their position indices. Accessing elements is comparatively easier this way. |
| Methods and Operations | We can perform only a limited set of operations on a stack, such as peek, pop, push, etc. | An array is very rich in operations/methods, such as pop, push, reverse, traversing, sorting, and many more. |
| When to Use | A stack is good when we are dealing with a dynamic process where we don’t know the data requirements. | An array is good to go when we are aware of the type of data that needs to be processed and might require a constant change in any element present in the array. |
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