Understanding custom comparators in sorting

Sorting is the process of arranging elements in a collection according to a specific order, such as ascending or descending. For primitive data types like integers, floating-point numbers, or characters, most programming languages provide built-in comparison using relational operators like < and > to establish the greater and smaller relationships.

However, real-world problems often involve sorting more complex data structures such as arrays, lists, maps, or instances of user-defined classes. In such cases, there is no inherent or default way to compare two elements. To sort these non-primitive data types, we need to define explicit rules that determine how one element should be ordered relative to another. This is often done using a custom comparator.