Declaring an array
You must declare an array before you can use it.
When you declare an array in C++, you create a data structure that contains the list of variables.
(This is not true in all programming languages.
For example, in Java, it is necessary to create an object that encapsulates the array and to declare a variable that points to the object as separate operations.
However, it is possible to combine both operations into a single statement in Java.)