DYNAMIC ARRAY

DYNAMIC ARRAY data type works in the same way as ARRAY data type but it has some additional features.

As opposed to static arrays, dynamic arrays do not have a fixed size. When you add a new element to the dynamic array, it resizes automatically (whereas it is impossible to write beyond the bounds of a static array).

Dynamic arrays can be single- and multi-dimensional.

Single-dimensional arrays have this syntax:

4GL data type

any Querix 4gl or user-defined data type except for ARRAY and DYNAMIC ARRAY

Multi-dimensional arrays have this syntax:

4GL data type	any Querix 4gl or user-defined data type except for ARRAY and DYNAMIC ARRAY
integer expression	a 4GL expression that denotes the number of array dimensions = a positive integer or a literal integer in the range from 1 to 3

Here is a example of how two-dimensional dynamic arrays are declared:

Here is a example of how three-dimensional dynamic arrays are declared:

Restrictions imposed on dynamic arrays

There is a number of restrictions imposed on dynamic arrays.

getLength() method is not supported for a whole array - only for its separate elements:

For example, for a two-dimensional dynamic array:

DEFINE a DYNAMIC ARRAY WITH 2 DIMENTIONS OF datatype

valid usage is a[index].getLength(), and

invalid usage is a.getLength() (will cause in a compile time error).

DISPLAY ARRAY can be used to display only arrays of the RECORD data type.

Array length must always be greater than 0. Otherwise, the program will fail to compile.

Using dynamic arrays

Dynamic arrays can be used in the DISPLAY ARRAY and INPUT ARRAY statements like static arrays. When used in the INPUT ARRAY statement, the array will be automatically resized when the cursor moves to a non-occupied row of the screen array as well as when the row is deleted.

Querix4GL also has a number of methods that can be used with variables of the DYNAMIC ARRAY data type:

variable.Method()

These methods serve as auxiliary tools used to manage the dynamic array effectively:

append()	adds a new element after the last element of the array
appendElement()	adds a new element with the NULL value to the array (takes no parameters)
insert()	inserts a new array element to the specified position
insertElement()	inserts an empty array element to the specified position
resize()	resizes the single-dimensional array to the specified size
getSize()	return the size of a single-dimensional array
delete()	removes all the specified array elements within the given range or at the given position
deleteElement()	removes the specified array element
clear()	removes all the elements
join()	concatenates all the elements of an array into a string