An array is a type that groups a number of variables of the same type. Examples are an array of char, an array of integer, and an array of real. In fact, any type, including user defined types, may be used in an array. However, the elements of an array are always of the same type. Different types cannot be grouped into an array. For this purpose, see records.
Arrays reflect the mathematical concept of
- vectors (one-dimensional array) and
- matrices (two-dimensional array)
The declaration works similar to that for simple types, but you need to add the number of elements via an index range, as well as the array element type.
program ... var variablename: array [startindex..endindex] of type; begin ...
startindex must be less than or equal to endindex, and both must resolve to an integer constant, either an integer value or a const value that is an integer. Either or both numbers may be negative or zero.
One-dimensional array example:
type simple_integer_array = array [1..10] of integer; var Numbers: simple_integer_array;
Multidimensional arrays are supported such as [x..y,z..t] and so on.
Multidimensional array example:
type more_complex_array = array [0..5,1..3] of extended; var specialmatrix: more_complex_array;
If it is not possible to know the exact number of array elements needed at the time of the program compilation, the dynamic array type can be used. A dynamic array can grow or shrink in size during program execution.
To access an array element you need to include the element position between brackets () along with the name of the array variable. The element can then be used like a simple variable. But if you want to use parameters you MUST use a structure because else it will cause errors or bugs... (I do not understand, what is meant here).
Var my_array : array[1..3] of Integer; my_matrix : array[1..5,1..5] of Integer; some_value : Integer; ... begin my_array := a + 2; my_matrix[2,3] := some_value; ... some_value := my_array; some_value := my_matrix[4,3]; end.
There are two formats used for array literals, depending on where they are placed. In the variable declaration section, you can initialize static arrays (it is not possible with dynamic arrays) with a series of values placed inside parentheses. In a statement block you can create an anonymous array with a series of values inside of brackets. For example:
Var // initialize static integer array via array literal Numbers : array [1..3] of Integer = (1, 2, 3); procedure PrintArray(input : array of String); var i : integer; begin for i := 1 to length(input) do write(input[i - 1],' '); writeln; end; begin Writeln( Numbers ); // create three item anonymous string array via an array literal PrintArray( ['one', 'two', 'three'] ); end.
one two three
|simple data types|
|complex data types|