What is the difference between an array’s size declarator and a subscript?

When we talk about arrays in the context of Java, we're referring to a fundamental data structure used to store a fixed-size sequential collection of elements of the same type. An array is used to consolidate data, allowing for efficient data manipulation and retrieval.

An array is declared with a specific data type and once declared, the type of elements it can hold is fixed. For example, an int array can only contain integers. Arrays in Java are objects, which means they are created dynamically and can be passed to methods or can be returned from methods.

To initialize an array in Java, you can either use the new keyword with the desired size or directly initialize it with the values, as shown in the examples below:

Array elements indexing is a way to access individual elements stored in an array. Each element in an array is accessed by its numerical index—think of it as a unique address for each slot in the array.

In Java, array indexes start at 0, so the first element of any array has an index of 0, the second element an index of 1, and so on. This zero-based indexing system is important to remember, as it is a frequent source of errors for beginners.

For example, if you have an array with 5 elements, the index range goes from 0 to 4. Here is how you might access the elements in a Java array:

Declaring arrays in Java is a straightforward process that involves specifying the type of elements the array will hold and its size. The size declarator in an array declaration indicates the number of elements the array can contain, whereas the subscript is used to access and manipulate specific elements within the array.

Declaring an array involves two main steps: declaration and instantiation. During declaration, you define the array's name and type. When instantiating, you use the new keyword to create the array and assign it to the declared array variable, which determines the size of the array. Here's the syntax for declaring and creating an array in Java: