Dynamic change of variable name

[Yveaux]

@greg_2502 do you mean to fill an array?
Something like

int value[5];
for (i=1; i<5; i++){
  value[i] = debouncer[i].read();
}

[skywatch]

@yveaux Shouldn't that be int value[4]; ? ;)

[mfalkvidd]

@skywatch not if the 0th position is skipped

[skywatch]

@mfalkvidd Hehehe...... ;)

But i starts at 1 yes? and then increments in interger units whilst it is less than 5. So that should give 1,2,3,4. Or have I been under a misunderstanding?

[mfalkvidd]

@skywatch arrays indexes in c/c++ always start at 0.
int myarray[5] would have positions 0 thorugh 4. Position 5 would be outside the array. In the code above, position 0 is never used.

So either make the array 1 element larger than actually needed (with position 0 unused), or let i start at 0:

int value[4];
for (i=0; i<4; i++){
  value[i] = debouncer[i].read();
}

[Sergio Rius]

@mfalkvidd said in Dynamic change of variable name:

int myarray[5] would have positions 0 thorugh 4. Position 5 would be outside the array. In the code above, position 0 is never used.

So either make the array 1 element larger than actually needed (with position 0 unused), or let i start at 0:

In fact, I interpreted it more like @skywatch
Notice the <=

 int value[5];
 for (i=1; i<=5; i++){
   value[i] = debouncer[i].read();
 }

I just made something like this for indexing sensors in a node, where idx 0 was the node itself, and thus already filled before the loop.

[Yveaux]

@sergio-rius said in Dynamic change of variable name:

Notice the <=

That will cause a buffer overrun at the end again...

[skywatch]

@yveaux Can you please explain why as I want to learn why it won't run the code the way I expected it to! -

[skywatch]

@mfalkvidd That won't get '0 through 4' as it will never produce i=4 in this case. I would expect it to need to be

int value[4];
for (i=0; i<=4; i++){
  value[i] = debouncer[i].read();
}

in order to get 0 through 4 (note the extra '=' in line 2 above to make this work. Or am I still misunderstanding something? ???

[Sergio Rius]

It's as easy as trying it.

@yveaux said in Dynamic change of variable name:

That will cause a buffer overrun at the end again...

Really? I can't see why a loop trough 1, 2, 3, 4 could overflow a 5 elements array.

In my code, I manually add 0 (the device itself, for vcc) before entering the loop. So in this case, still 5 elements.

[badmannen]

@sergio-rius
the loop will run even at "5".
that is the problem. if you write "i<5" , then it would be ok

[Sergio Rius]

@badmannen @Yveaux You're absolutely right. I was lazy, only changed a symbol and gave a bad advice. My response should be changed to <=4.

Still I don't understand what the original question was.