A nonpointer array occupies a sequence of contiguous storage sequences, one for each array element, in array element order.
Two or more arrays are associated when each one is associated with the same storage location. They are partially associated when part of the storage associated with one array is the same as part or all of the storage associated with another array.
If arrays with different data types are associated (or partially associated) with the same storage location, and the value of one array is defined (for example, by assignment), the value of the other array becomes undefined. This happens because an element of an array is considered defined only if the storage associated with it contains data of the same type as the array name.
An array element, array section, or whole array is defined by a DATA statement before program execution. (The array properties must be declared in a previous specification statement.) During program execution, array elements and sections are defined by an assignment or input statement, and entire arrays are defined by input statements.
For More Information: