One-, two-, and three-dimensional fields (arrays) are supported as elementary data types. Arrays can be defined both in the declaration part of a POU and in the global variable lists. Maximum 9 dimensions may result from nesting of arrays ( "ARRAY[0..2] OF ARRAY[0..3] OF …" ).
Syntax:
<Field_Name>:ARRAY [<ll1>..<ul1>,<ll2>..<ul2>]
OF <elem. Type>.
ll1, ll2, ll3 identify the lower limit of the field range; ul1, ul2 and ul3 identify the upper limit. The limit values must be integers and must match the DINT range of values.
Example:
Card_game: ARRAY [1..13, 1..4] OF INT;
Initializing arrays:
Example for complete initialization of an array:
arr1 : ARRAY [1..5] OF INT := 1,2,3,4,5; arr2 : ARRAY [1..2,3..4] OF INT := 1,3(7); (* short for 1,7,7,7 *) arr3 : ARRAY [1..2,2..3,3..4] OF INT := 2(0),4(4),2,3; (* short for 0,0,4,4,4,4,2,3 *)
Example of the initialization of an array of a structure:
TYPE STRUCT1 STRUCT p1:int; p2:int; p3:dword; END_STRUCT ARRAY[1..3] OF STRUCT1:= (p1:=1,p2:=10,p3:=4723),(p1:=2,p2:=0,p3:=299),(p1:=14,p2:=5,p3:=112);
Example of the partial initialization of an array:
arr1 : ARRAY [1..10] OF INT := 1,2;
Elements to which no value is pre-assigned are initialized with the default initial value of the basic type. In the example above, the elements anarray[6] to anarray[10] are therefore initialized with 0.
Accessing array components:
Array components are accessed in a two-dimensional array using the following syntax:
<Field_Name>[Index1,Index2]
Example:
Card_game [9,2]
If you define a function in your project with the name CheckBounds, you can use it to check for range overflows in your project.