I have array on structure target (x: byte, y : byte).

var1 : array [1..30] of target;

actual_var : pointer to target;

value := actual_var^[5].x; ( didn't work )

actual_var := actual_var + ( sizeof(target) * 5); ( didn't work )

Where is problem?

Thanks Paul

Hi Paul!

Zitat:
value := actual_var^[5].x; ( didn't work )

Your Pointer is no array of something so you cant use indexes

Zitat:
actual_var := actual_var + ( sizeof(target) * 5); ( didn't work )

Only sizeof(Variable) not Sizeof(Datatype) is possible.

See the solutions below:

VAR
   var1 : ARRAY [1..30] OF target;
   actual_var : POINTER TO ARRAY [1..30] OF target;
   actual_var2: POINTER TO target;
   value: BYTE;
   value2: BYTE;
END_VAR
actual_var:= ADR(var1);
value := actual_var^[5].x; (* works *)
actual_var2:= ADR(var1);
actual_var2 := actual_var2 + SIZEOF(actual_var2^) * DWORD#4; (* works *)
value2:= actual_var2^.x;

Ist there any information about pointer arithmetic in st?

Try and error is a bad solution for me.