When you are first learning how to code, it can be easy to confuse Array and ArrayList. Both data structures allow you to store multiple values in a single variable, but they have some key differences. In this blog post, we will take a closer look at those differences and explain why you might use one over the other. Stay tuned!
What is Array?
The array is a data structure that can be used to store the linear collection of data. In an Array, each element is assigned a contiguous block of memory. The size of the Array is fixed, i.e., it cannot be increased or decreased once it is created. The array is a static data structure. The array allows random access to elements.
- That means we can access any element in an Array by using its index. Array elements are stored in consecutive memory locations. The array uses a direct addressing scheme. The array is used to store homogeneous collections of data. For example int array, double array, char array, etc. We cannot store heterogeneous collections of data in an Array. Array index starts from 0.
- The first element of the Array is stored at the 0th index and the last element of the Array is stored at (n-1)th index where n is the size of an Array. Each and every element in an Array occupies an equal amount of memory space. If we want to store ‘n’ elements in an Array then we must declare an Array of size ‘n’.
- We can insert new elements at the end of an Array but we cannot insert new elements in between the existing elements in an Array because Array does not allow dynamic memory allocation. We can delete existing elements from an Array but after deleting the elements, there will be vacant memory locations (known as Dangling Memory Locations) in between the existing elements.
What is ArrayList?
ArrayList is a data structure that stores a collection of objects. It is similar to an array, but it can grow and shrink as needed. ArrayLists are very efficient for adding, removing, and accessing elements. They are also easy to use and manipulate. ArrayLists are a great choice for data structures when you need to store a lot of data.
Difference between Array and ArrayList
Array and ArrayList are two data structures that are used to store data in a computer. The array is a data structure that stores data in a linear fashion, while ArrayList is a data structure that stores data in a dynamic fashion. ArrayList is often used when the size of the data is not known in advance, while Array is used when the size of the data is known in advance. ArrayList is more flexible than Array, but it is also slower. The array is faster than ArrayList because it uses less memory.
In conclusion, arrays are better when you know the size of the data set in advance. If you don’t know the size of the data set or if it is likely to change, use an ArrayList.