[Solved] Weird problem can somebody explain please?

Using Arduino Programming Questions
#1

A couple of nights ago on another thread http://forum.arduino.cc/index.php?topic=289183.msg2026221#msg2026221, Paul__B was helping solve a problem.

Now the last post on that thread was me asking if someone could tell me what this :-

((total+)/10)

was.

Now it has just become more confusing, when Paul posted his code

double R1[4] = {
  8000.00, 4000.00, 2000.00, 1000.00};
double R2 = 90.00;
int total;
//int V = 5;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  int s1, s2, s3, s4;
  double effective;
  for (int n = 0; n < 16; n++) {
    effective = 0.00;
    s4 = (n & 0x08 ? 1 : 0);
    Serial.print(s4);
    Serial.print(" ");
    s3 = (n & 0x04 ? 1 : 0);
    Serial.print(s3);
    Serial.print(" ");
    s2 = (n & 0x02 ? 1 : 0);
    Serial.print(s2);
    Serial.print(" ");
    s1 = (n & 0x01 ? 1 : 0);
    Serial.print(s1);
    Serial.print(" ");
    if (s1) effective = effective + (1 / R1[0]);
    if (s2) effective = effective + (1 / R1[1]);
    if (s3) effective = effective + (1 / R1[2]);
    if (s4) effective = effective + (1 / R1[3]);
    effective = (1 / effective);
    //    Serial.print(effective);
    //    Serial.print(" ");
    total = (1023-((effective / (R2 + effective)) * 1024));
    Serial.print(total);
    Serial.print("   ");
    Serial.print((total+)/10); // Note "linearising" tweak
    Serial.println(" ");
  }
}

void loop() {
  // put your main code here, to run repeatedly:

}

It compiled and ran without error, now I am trying to compile again, and I get an error. I have tried this on IDE 1.5.7 IDE 1.6.0 and IDE 1.0.6 all give

sketch_jan02a.ino: In function ‘void setup()’:
sketch_jan02a.ino:36:26: error: expected primary-expression before ‘)’ token

I even tried a restart of my computer, no different.

Can ANYBODY tell me what that function is… and why it is not now working for me.

Thanks,

Graham

#2

According to that error message, it is in line 36.

I have never seen ( total+ ) / 10 in my whole life. As far as I know it is nonsense.

#3

((total+)/10) is not a valid expression. Either put something after the "+", or perhaps it is meant to be "++"?

Regards,
Ray L.

#4

I appreciate what you are saying, and I am very well aware of the error I am receiving, but did you read all of my original post? That code compiled and ran when I tried it 2 days ago!!!

So can I reiterate.... What does that function do, and why is not working for me now?

Thanks,

Graham

#5

It's the total+ that is causing the problem

Mark

#6

ghlawrence2000:
I appreciate what you are saying, and I am very well aware of the error I am receiving, but did you read all of my original post? That code compiled and ran when I tried it 2 days ago!!!

So can I reiterate.... What does that function do, and why is not working for me now?

Thanks,

Graham

I can't explain what I can't see. What I can tell you for certain is that the code, as it is here, absolutely did NOT compile. That line is not valid c syntax.

Regards,
Ray L.

#7

A couple of nights ago on another thread http://forum.arduino.cc/index.php?topic=289183.msg2026221#msg2026221, Paul__B was helping solve a problem.

There are two sketches in that thread one with the total+ construct and one without,
only one of them compiles..

#8

When code is bad, don't ask yourself why it did work before. Bad is bad. Fix it.
I don't know what that code does. Is it code for the Arduino Due, or the normal Uno/Nano/Micro boards ?

#9

The only way that code compiled is if you included a library that provided an operator definition for a post-fix +, which is pretty unlikely.

The is C++, not C, remember, so operator syntax can be updated.

#10

Ok, so lets take this from a different angle…

If we just use (total/10) the result is :-

0 0 0 0 0   0 
0 0 0 1 10   1 
0 0 1 0 21   2 
0 0 1 1 32   3 
0 1 0 0 43   4 
0 1 0 1 53   5 
0 1 1 0 63   6 
0 1 1 1 73   7 
1 0 0 0 83   8 
1 0 0 1 93   9 
1 0 1 0 102   10 
1 0 1 1 111   11 
1 1 0 0 120   12 
1 1 0 1 129   12 
1 1 1 0 138   13 
1 1 1 1 146   14

Whereas what is actually wanted is :-

0 0 0 0 0   0 
0 0 0 1 10   1 
0 0 1 0 21   2 
0 0 1 1 32   3 
0 1 0 0 43   4 
0 1 0 1 53   5 
0 1 1 0 63   6 
0 1 1 1 73   7 
1 0 0 0 83   8 
1 0 0 1 93   9 
1 0 1 0 102   10 
1 0 1 1 111   11 
1 1 0 0 120   12 
1 1 0 1 129   13 
1 1 1 0 138   14 
1 1 1 1 146   15

This was the result of ((total+)/10). I really cannot explain why it did work… So assume, I imagined it… how do we linearise the list shown… (using code that works)?

Thanks,

Graham

Edit: Ok so I must have dreamed it worked… I see if we use ((total+5)/10) That works and is actually syntax I understand :wink:

#11