a simple "printf" function

Hi, Clem:

These types of errors are typically caused by stray unprintable characters in the source; the compiler objects to them as they don't fit the defined syntax.

It might be helpful if you posted the actual source code and corresponding error messages.

HTH,

Another possible source of trouble, is terminal character encoding set. Maybe you are using ISO-8859, and program is using UTF-8, or viceversa.

Most likely, you've got a non-printable character in your code.

You can see it opening the file in an hex editor.

Long time ago when I wrote a developer text editor, I had a lot of troubles with weird text people copied from the web, and  then reported problems in how my program managed those chars.

Also many people using shift+space and shift+ ... combinations inadvertently, ended up with weird non printable characters in their documents.

To help me debug those I did a tiny executable to dump the offending parts. I'm posting it here but for a whole document the hex editor is much better.

#include <stdio.h>

#include <string.h>

#include <errno.h>

int main (int argc, char **argv)

{

        FILE *f;

        int c, i=1;

        if( argc != 2 ){

                printf("Ussage: %s file\n", argv[0]);

                return 0;

        }

        f = fopen(argv[1],"r");

        if( f == NULL ){

                printf("%s\n", strerror(errno));

                return -1;

        }

        printf("%d: ",i);

        while((c = fgetc(f))!= EOF){

                if( c == '\n') printf("\n%d:", ++i);

                else printf( "'%c'=>'%d' ", c, c);

        }

        printf("\n");

        return 0;

}

It just dumps the decimal value of the character and the printable representation of that character.

As example the output for a file containing the word "test", it would be:

1: 't'=>'116' 'e'=>'101' 's'=>'115' 't'=>'116'

It may help or not, and will for sure fail with UTF-8 or any multi byte encoding, but most source code is ascii.

It helped me when trying to deal with those pesky non printable characters.

Use it at your convenience.

Iago Rubio wrote:

 

Most likely, you've got a non-printable character in your code.

 

You can see it opening the file in an hex editor.

You can also use the GNU command "hd" (hex dump) at the command line.

//Include standard io

#include <stdio.h>

#include <stdlib.h>

//Include ArduPi library

#include "arduPi.h"

//Include the Marth library

#include <math.h>

//Needed for Serial Communication

SerialPi Serial;

//Needed for accessing GPIO (pinMode, digitalWrite, digitalRead,

//I2C funcions)

WirePi Wire;

//Needed for SPI

SPIPi SPI;

//Values need for Steinhart-Hart equation

//and calculating resistance.

#define TENKRESISTOR 10000 //our 10K resistor

#define BETA 4000 // This is the Beta Coefficient of your thermistor

#define THERMISTOR 10000  //The resistance of your thermistor at room temp

#define ROOMTEMP 298.15 // standard room temperature in Kelvin (25 Cesius).

//Number of readings to take

//these will be averaged out to

//get a more accurate reading

//You can increase/decrease this as needed

#define READINGS 7

int main() {

  setup();

  while(1) {

  loop();

  }

  return(0)    ;

}

void setup(void){

  printf(¨Starting up thermometer\n¨);

  Wire.begin();

}

void loop(void) {

  float avResistance;

  float resistance;

  int combinedReadings[READINGS];

  byte val0;

  byte val1;

  //Our temperature variable

  float kelvin;

  float fahrenheit;

  float celcius;

  int channelReading;

  float analogReadingArduino;

  /***********************

  ADC mappings

  Pin Adress

  0 0xDC

  1 0x9C

  2 0xCC

  3 0x8C

  4 0xAC

  5 0xEC

  6 0xBC

  7 0xFC

    ****************/

//0xDC is our analop 0 pin

Wire.beginTransmission(8);

Wire.write(byte(0xDC));

Wire.endTransmission();

/* Grad the two bytes returned from the analog 0 pin, combine them

  and write the value to the combinedReadings array

*/

for(int r=0; r<READINGS; r++) {

  Wire.requestFrom(8,2);

  val0 = Wire.read();

  val1 = Wire.read();

  channelReading = int(val0)*16 + int(val1>>4);

  analogReadingArduino = channelReading * 1023 / 4095;

  combinedReadings[r] = analogReadingArduino;

  delay(100);

}

//Grab the average of our 7 readings

//in order to get a more accurate value avResistance = 0;

for (int r=0; r<READINGS; r++) {

  avResistance += combinedReadings[r];

}

avResistance /= READINGS;

/* We can now calculate the resistance of the readings that have come

* back from analog 0

*/

avResistance = (1023 / avResistance) - 1;

avResistance = TENKRESISTOR /avResistance;

resistance = avResistance / THERMISTOR;

//Calculate the temperature in Kelvin

kelvin = log(resistance);

kelvin /= BETA;

kelvin += 1.0 / ROOMTEMP;

kelvin = 1.0 / kelvin;

//printf(¨Temperature in K ¨);

//printf(¨%f \n¨,kelvin);

//Convert from Kelvin to Celsius

celcius = kelvin -= 273.15;

// printf(¨Temperature in C ¨);

//printf(¨%f \n¨, celsius);

//Convert from Celsius to Fahrenheit

fahrenheit = (celcius * 1.8) + 32;

//printf(¨Temperature in F ¨);

//printf(¨%f \n¨, fahrenheit);

//Three second delay before taking our next reading

delay(3000);

}

Hi, Clem:

On line 58 of your program the "quote" marks are encoded as 0xC2 0xA8 (Octal 302 and 250) rather than as 0x22 (the normal ascii quotation mark) .. actually, all of the quotation marks within the printf statements are that way, but as all of the other printf statements are commented out they're ignored by the compiler Interestingly enough the other quote marks were as expected.

HTH,

Bruce

Right on the spot Bruce.

That happens a lot when you copy and paste from the web and Word Clem.

What text editor are you using ?

I've never seen a developer editor doing that, and on most of them syntax highlighting would be wrong with this code.

Hi Iago,

            I am very new to this platform and I am just following what was written in the book, I typed all of them manually, the book recommended to use Geany but it seems this is the culprit but in its bottom line, the mode = Unix; encoding: UTF-8.  What editor can you suggest please.

Best regards,

Clemzky

Hi Bruce,

              Could you share how you managed to do that for the sake of the rest of newbies that might be reading this, as this will be very helpful.  What editor do you use?

Bruce and Iago, thanks you guys for helping and spending time to answer my questions.

Best regards,

Clemzky

Hi Iago, Bruce and John,

                                      Thank you for leading the way, now I can move on, for now I do not think of any Hex Editor, I just downloaded the Eclipse for windows and from there opened up my source code and bingo!! there are special characters, from there I edited the source accordingly and move it to Pi, compiled and works.  If my memory serves me right, there is Eclipse for Pi but not sure, now searching for it to be loaded in the PI as an editor and compiler. Kudos to all of you guys!!!!

Best regards,

Clemzk