Question

I dont know if this is possible, but help give suggestions.

I have a variableunsigned char Var_2_insert; and I have an array const unsigned char insert_here[4];.

This variable is initialized at run time say var_2_insert = 225;. The idea is that index 3 in the array should have the value of var_2_insert always. So I want to try something like

insert_here[4] = { 0x00, 0x02, 0x03, Var_2_insert};

So that any time I try to read the array insert here, It will have the present value of var_2_insert. Now I know if I go like this:

#define Var_2_insert 225

This will go well, but since this variable has to be updated at runtime, I tried

#define _VAR Var_2_insert
insert_here[4] = { 0x00, 0x02, 0x03, _VAR};

But does not work. So how can i go about this? I hope my question is clear enough.

Thanks.

Answer 1

What you can do is have Var_2_insert a pointer to the 3rd index in the array:

unsigned char insert_here[4]; // since it's updating it shouldn't be const
unsigned char *Var_2_insert = &(insert_here[3]);
//you just need to update the use of var_2_insert to dereference..
//  var_2_insert = 225 // <-- before
   *var_2_insert = 225 // <-- after