Assign a value from sd card to a BigNumber variable

[Matteode]

Hi Nick! I am trying to use your library (BigNumber) but i have a problem. I'm trying to read numbers from a sd card and to take last value assigning it to a variable . I stored values as BigNumber with this sketch:

include "BigNumber.h"

include

include

File myfile; BigNumber pot=A3, input1, input2, d1, d2, valoreatt, valoreacc=0;

void printBignum (BigNumber n){ char * s = n.toString (); Serial.println (s); free (s); } // end of printBignum

void setup() {

Serial.begin(9600);
pinMode(10, OUTPUT);
//verifico l'esistenza di una memory card
if (!SD.begin(10)) {
Serial.println("Card failed");
return;
}
Serial.println("card inizialized");
BigNumber::begin (20);  // initialize library
input1 = analogRead(pot);

}

void loop() {

if (valoreacc<1){
input2 = analogRead(pot);

d1 = BigNumber (input2) / BigNumber (1023);
d2 = BigNumber (d1) * BigNumber (d1) * BigNumber (d1);
valoreatt = BigNumber (d2) / BigNumber (125) / BigNumber (1000); 
valoreacc = BigNumber (valoreatt) + BigNumber (valoreacc);

Serial.print ( "input: " );    
printBignum (input2);
Serial.print ( " valoreatt: " );
printBignum (valoreatt);
Serial.print ( " valoreacc: " );  
printBignum (valoreacc);  

// memorizzo il danno sulla sd card
myfile = SD.open("valori.csv", FILE_WRITE); 
if (myfile) { 
myfile.println( valoreacc );
myfile.close();   
}
input1=input2;
delay(1500);
}
else { 
Serial.print( "stop" );    
}

}

An example of numbers stored is this:

0.00000069004655222191 0.00000138009310444382 0.00000207013965666573 0.00000276018620888764 0.00000345023276110955 0.00000414027931333146 0.00000483032586555337 0.00000552037241777528 0.00000621041896999719 0.00000690046552221910 0.00000759051207444101 0.00000828055862666292 0.00000897060517888483 0.00000966065173110674

Then I tried to take last value with this sketch:

include "BigNumber.h"

include

include

File myFile;

BigNumber valore;

void printBignum (BigNumber n){ char * s = n.toString (); Serial.println (s); free (s); } // end of printBignum

void setup(){ Serial.begin(9600); Serial.println("Initializing SD card..."); pinMode(10, OUTPUT); digitalWrite(10, 1); BigNumber::begin (20); // initialize library

if (!SD.begin(10)) { Serial.println("initialization failed!"); }

char c; String inString = String();

myFile = SD.open("valori.csv"); if (myFile) { while (myFile.available()) {

   while(c != -1) {
      c = myFile.read();

      if(!myFile.available()) break;                   
      if (c == '\n') inString = "";          
      inString += c;   
  }           
}
myFile.close();

}

// -----------questa è la tua ultima riga ---------- Serial.println(inString); //debug //--------------------------------------------------

valore = inString.toInt(); Serial.print ( " valore: " );
printBignum (valore);

}

void loop(){
}

It finds last value but i don't succeed to assign it to variable "valore" to do then others math operations. It gives me 0.

[nickgammon]

Answered here:

http://forum.arduino.cc/index.php?topic=85692.105