String not coveting to int.

Gmanski · November 8, 2018, 2:14pm

I'm writing a program to get the list of values of a SD card file into usable values but the string value will not convert to a int variable. The SD card file is taken from a app I built. The string that is taken from the SD card file is laid out as the following example.

List of values from app: {000.00, 123.45, 098.70, 656.00}

SD card file is laid out as: 000.00123.45098.70656.00

I'm able to put the string into char and get the individual values in the list to its own string, but when I go to set that string it does not work. Example follows:

String: 000.00

Serial Print String to int:

<
+

The part of the code where I'm attempting to the string to int is under void draw().

#include <Wire.h>
#include "rgb_lcd.h"
#include <SPI.h>
#include <SD.h>
#include <Stepper.h>

const int stepsPerRevolution = 1000;
String Yval = "";
int view = 0;
char FileChar[] = {"oof"};
char FileChar2[] = {"oof"};
int i = 0;
String Xval = "";
const int chipSelect = 4;
rgb_lcd lcd;
const int colorR = 0;
const int colorG = 0;
const int colorB = 0;
int TouchSec = 0;
int Version = 1.0;
char* Main[]= {"Print", "Information", "Options"};
int delayTime = 100;
String Select = "SELECT";
char Ymap[] = {"fun"};
char Xmap[] = {"fun"};
int X1 = 10;
int Y1 = 20;
int X2 = 10;
int Y2 = 20;
int TransX = 0;
int TransY = 0;
int Line = 0;
int slope = 0;
int Rise = 0;
int Run = 0;
int Rest = 0;
int Draw = 180;
int numX = 0;
int placeX = 0;
String CurentX = "";
int numY = 0;
int placeY = 0;
String CurentY = "";

Stepper myStepper(stepsPerRevolution, 14,15,16,17);
int val = 0;
void setup() {
	
	 myStepper.setSpeed(150);
	int view = 1;
  // put your setup code here, to run once:
  lcd.begin(16, 2);
  lcd.setRGB(colorR, colorG, colorB);
  clearScreen(); 
  lcd.setRGB(200 , 255, 200);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (digitalRead(8) == 1){
  	TouchSec++;
  	Print();
  	delay(500);
  }else{
  	TouchSec = 0;
 }
 if (view == 1)
  clearScreen();
   
   
}

void clearScreen() {
	Select = String(Main[TouchSec]);
  lcd.setCursor(0, 0);
  lcd.print("CNC PLOTTER V1.0");
  
  if (TouchSec == 0){
  	lcd.setCursor(0, 1);
 lcd.print("    <" + Select + ">    ");
  }
  if (TouchSec == 1){
  	lcd.setCursor(0, 1);
 lcd.print(" <" + Select + ">  ");
  }
  if (TouchSec == 2){
  	lcd.setCursor(0, 1);
 lcd.print("   <" + Select + ">   ");
  }
  
}
void Print() {
 myStepper.step(-60);

lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Initializing ");
lcd.setCursor(0, 1);
  lcd.print("SD Card...");
  delay(1000);
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
  	lcd.clear();
  lcd.setCursor(0, 0);
   lcd.setRGB(255 , 5, 5);
    lcd.print("Card failed");
     lcd.setCursor(0, 1);
   lcd.setRGB(255 , 5, 5);
    lcd.print("or is not present");
    // don't do anything more:
    while(1);
    delay(1000);
  }
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Card Initialized.");
   myStepper.step(120);
delay(1000);
   // re-open the file for reading:
File  myFile = SD.open("X.TXT");
  if (myFile) {
    // read from the file until there's nothing else in it:
    while (myFile.available()) {
    	char FileChar = myFile.read();
    	Xval = Xval + String(FileChar);
     } 
     
     Serial.println("XmapCheck:   " + String(Xmap));
      myFile.close();
     File myFile = SD.open("Yval.TXT");

  // if the file is available, write to it:
  if (myFile) {
    while (myFile.available()) {
      	char FileChar2 = myFile.read();
    	Yval = Yval + String(FileChar2); 
    
    }
   	myFile.close();
     lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Complete");
   lcd.setRGB(5 , 255, 5);
  Yval.toCharArray(Ymap, (Yval.length() + 1));
    lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("done");
  wouldYouPrint();
   
   
    }
  // if the file isn't open, pop up an error:
  else {
  	 lcd.clear();
  	  lcd.setRGB(255 , 5, 5);
  lcd.setCursor(0, 0);
  lcd.print("Error Opening");
  lcd.setCursor(0, 1);
  lcd.print("File(s)");
  }
  }
  
  
}


	


void Info() {
	
}
void Settings() {
	
}
void wouldYouPrint() {
Line = 0;
numX = 0;

 Serial.println("Ymap:   " + String(Ymap));
  draw();
}
void draw(){
Xval.toCharArray(Xmap, (Xval.length() + 1));
    //get X1
    numX = Line;
    placeX = numX * 6;
 	CurentX = "";
 	CurentX = String(CurentX + String(Xmap[placeX]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 1)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 2)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 3)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 4)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 5)]));
 	X1 = (CurentX.toInt());
	Serial.println("X1: " + X1);
	Yval.toCharArray(Ymap, (Yval.length() + 1));
	//get Y1
	numY = Line;
	placeY = numY * 6;
 	CurentY = "";
 	CurentY = String(CurentY + String(Ymap[placeY]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 1)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 2)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 3)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 4)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 5)]));
 	Y1 = (CurentY.toInt());
 Serial.println("Y1: " + Y1);
 Xval.toCharArray(Xmap, (Xval.length() + 1));
 	//get X2
 	numX = (Line + 1);
    placeX = numX * 6;
 	CurentX = "";
 	CurentX = String(CurentX + String(Xmap[placeX]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 1)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 2)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 3)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 4)]));
 	CurentX = String(CurentX + String(Xmap[(placeX + 5)]));
 	X2 = (CurentX.toInt());
Serial.println("X2: " + X2);
Yval.toCharArray(Ymap, (Yval.length() + 1));
	//get Y2
	numY = (Line + 1);
	placeY = numY * 6;
 	CurentY = "";
 	CurentY = String(CurentY + String(Ymap[placeY]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 1)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 2)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 3)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 4)]));
 	CurentY = String(CurentY + String(Ymap[(placeY + 5)]));
 	X2 = (CurentY.toInt());
 Serial.println("Y2: " + Y2);
	//get slope
	slope = ((Y2 - Y1) / (X2 - X1));
	Serial.println(slope);
	TransX = X1;
	TransX = X1;
  
  lcd.setCursor(0, 0);
  lcd.print(String("Start: [X:" + X1));
  lcd.setCursor(0, 1);
  lcd.print(String("End: [X:" + X1));
	
}
void Translate(){
	if (!(X1 == X2)){
	if (X1 > X2){
		TransX++;
	}else{
		TransX--;
	}
	TransY = TransY + slope;
	Translate();
	}else{
	 Line++;
	 draw();
	}
	
}

system · November 8, 2018, 2:34pm

I tried to read you code. I nearly vomited. Use Tools + Auto Format BEFORE posting code that looks like that crap.

You clearly need to (re-)read the documentation for toCharArray(). The second argument is NOT the length of the String instance. The instance already KNOWS how long it is. It does not need your ham-fisted help.

Your extreme abuse of the String class is sickening.

The String class' + operator KNOWS how to concatenate a char or a string or a String to an EXISTING String. It is NOT necessary to create and destroy two MORE String instances to add ONE char to a String.

Printing the contents of the String before calling toInt() just might whack you with a clue-by-four.

Perehama · November 8, 2018, 2:44pm

Integers don't have decimals, so the decimal will be truncated using string.toInt(). string.toFloat() would preserve the floating point value, but the Arduino UNO really doesn't have a floating point math unit, so consider moving the math up a few significant digits so your values are all integers.
no one likes the String class as it can corrupt your memory. Consider replacing it's use with c-style strings.
if you use c-style strings, you can use atoi() or atol() among other useful standard library functions.

hammy · November 8, 2018, 2:47pm

With these type of problems it’s worth writing a short bit of code addressing the problem area - it’s easier to get working and debug it before you add to your program.

Try that , then post up the problem, if you still have it .

Topic		Replies	Views
converting a string to int - reading file from SD Card Programming Questions	14	3606	May 5, 2021
How to convert String to Int Programming Questions	8	11090	May 5, 2021
Convert Char to Int Programming Questions	10	3143	May 5, 2021
Reading from SD card to string and to int Programming Questions	23	1611	May 5, 2021
SD card issue with a file Programming Questions	2	580	May 6, 2021

String not coveting to int.

Related Topics