Question

i need to declare an array with user-defined dimension. This array is inside a pretty big program and change to a list can be pretty a problem.

Now my array is declared like this:

Buffer: array[0..myCostant * 2] of Byte;

and myCostant is, like it says, an already defined constant.
Now i need to use a variable, getting something like this:

Buffer: array[0..myVar * 2] of Byte;

but i can’t use variables inside array definition.

How i can solve this without changing my array in something else?
This variable is upper-bounded so can i declare array with this max size and reduce it with another instruction?

Answer 1

You should use dynamic arrays:

var
  Buffer: array of Byte;

begin
  SetLength(Buffer, myVar*2 + 1);

Alternatively, you can use a static array of the known upper-bound length and record the current ‘meaningful’ length of the array in a variable, say CurrentLength.

Then you can replace, for instance,

for i := 0 to Length(Buffer) - 1 do
  SomethingWith(Buffer[i]);

by

for i := 0 to CurrentLength - 1 do
  SomethingWith(Buffer[i]);