Index of Array with Max Value

Projects Programming
1

Hallo everybody,

I´m a bit confused:

I exactly used this example,

http://forum.arduino.cc/index.php/topic,41999.0.html#lastPost

to geht the Index of my Array with max value and other users confirmd, that this example will do ist.
But if I use it in my code:

int ls[3]={0};

int getIndexOfMaximumValue(int* array, int size){
  int maxIndex = 0;
  int max = array[maxIndex];
  for (int i=1; i<size; i++)
   {
    if (max<array)     <---- Error in this Line  ISO C++ forbids comparison between pointer and integer
    {
      max = array;
      maxIndex = i;
    }
  }
  return maxIndex;
} 

void setup() 
{}

void loop() 
{
  
 
  ls[0] = analogRead(A0);
  ls[1] = analogRead(A1);
  ls[2] = analogRead(A2);
  ls[4] = analogRead(A3);
  
 int a=getIndexOfMaximumValue(ls,4);
    
}

It says ISO C++ forbids comparison between pointer and integer...

I still have problems using pointers.
Thanks a lot for your help!

2

The example you took wasn't posted with code tags and the forum software broke it. Should be:

    if (max<array[i])     <---- Error in this Line  ISO C++ forbids comparison between pointer and integer
    {
      max = array[i];
      maxIndex = i;
    }

Not sure why your index starts at 1 rather than 0 though.

3

I just copied that from the old forum thread.
But I Think, you ar right. Should start with 0... :cold_sweat: But that wont solve the Problem...

4

I don't think putting four values into a three element array is such a bright idea.

if (max<array)

If that really is your code, then the compiler is absolutely correct.
Did you forget the subscript?

5

that wont solve the Problem...

No, but wildbill's post will, did you read that?

Also this

  int ls[3]={0};
  ...
  ls[4] = analogRead(A3); // loading the 5th byte of a 3-byte array!!

is a problem. And other places your consider the array to be 4 bytes in size.

Rob

6

Of course you are right, The Array was too small. Ich changed it.

Thanks everybody for help, I havent seen the tiny [ i ] in wildbill´s Post. Now everything works fine!

I´m tyring to kalibrate some Phototransistors, to follow an light soure. First results:

There are 4 (should be 6 but only had 4) in a hexagonal box, arranged concentric and each of it is shielded to the others.
After I found the Index with the brightest Sensor (that was the reason for my question above) and a second if loop if the right or left one is brighter, I get the angle to 30°... After that I will do a calibration with Gauss squares error method. I hope to get the angle of my "lightsource" within a error of a few degrees... ( I did that with once with a Multi-hole probe for wind cancels)

Turn your face to the sun, the shadows will fall behind you.... kind of working title. :slight_smile:

7

Not sure why your index starts at 1 rather than 0 though.

Because the 0 case is the one you have initialised with and there is no point comparing it to itself:

  int maxIndex = 0;
  int max = array[maxIndex];
  for (int i=1; i<size; i++)