Problem while using Structure

Projects Programming
1

Hello,

I have a function took String as CSV text ( "text,text,text,...,#") then return array of Strings contain the sub-strings witch is inside this CSV string. after that i use this array to set data into class variables, with Set functions that was already built.

I refer the this link https://www.geeksforgeeks.org/return-local-array-c-function/ to build the Structure and the function and they are working properly.

but while I tried to call the function from the void loop() it returned arrays took the exact values mentioned , but when i tried to call it from another function it returns a empty value.

I defined my Structure:

**struct arrStructure { **

** String arr[100]; **
};

And this is my function:

struct arrStructure distrCsvMsgIntoStrgAry(String csvData)
{
** int commasCount = 0;**
** for (unsigned int i = 0; i < csvData.length(); i++)**
** if (csvData.charAt(i) == ',')**
** commasCount++;**

** int partsCount = commasCount + 1; **
** struct arrStructure stringTo;**

** int partsIndex = 0;**
** int indexOfComma = csvData.indexOf(','); **
** while (partsIndex < partsCount)**
** {**
** stringTo.arr[partsIndex] = csvData.substring(0, indexOfComma);**
** csvData = csvData.substring(indexOfComma + 1, csvData.length()); **
** indexOfComma = csvData.indexOf(','); **
** partsIndex++;**
** }**
** return stringTo; **
}

when i need covert CSV String data to Array of Strings :

String dataRecived="confS,A,0,0,150,-5,6,70000,4-20mA,Flow Meter,m3//hr,#";

struct arrStructure stringTo = distrCsvMsgIntoStrgAry(dataRecived);

Serial.println(stringTo.arr[0]); Serial.println(stringTo.arr[1]); Serial.println(stringTo.arr[2]);

when i type this orders inside the void loop() the serial print :
confS
A
0

but if i use same 3 line within another function inside my Program, the serial returns empty values.

kindly help me to solve my problem

Thank you

2

Hello,

I have a function took String as CSV text ( "text,text,text,...,#") then return array of Strings contain the sub-strings witch is inside this CSV string. after that i use this array to set data into class variables, with Set functions that was already built.

I refer the this link https://www.geeksforgeeks.org/return-local-array-c-function/ to build the Structure and the function and they are working properly.

but while I tried to call the function from the void loop() it returned arrays took the exact values mentioned , but when i tried to call it from another function it returns a empty value.

I defined my Structure:

struct  arrStructure { 

   String arr[100]; 
};

And this is my function:

struct arrStructure distrCsvMsgIntoStrgAry(String csvData)
{
  int commasCount = 0;
  for (unsigned int i = 0; i < csvData.length(); i++)
    if (csvData.charAt(i) == ',')
      commasCount++;


   int  partsCount = commasCount + 1;        
   struct arrStructure stringTo;
                       
   int partsIndex = 0;
   int indexOfComma = csvData.indexOf(',');       
   while (partsIndex < partsCount)
   {
     stringTo.arr[partsIndex] = csvData.substring(0, indexOfComma);
     csvData = csvData.substring(indexOfComma + 1, csvData.length());      
     indexOfComma = csvData.indexOf(',');                                          
     partsIndex++;
   }
 return stringTo; 
}

when i need covert CSV String data to Array of Strings :

String dataRecived="confS,A,0,0,150,-5,6,70000,4-20mA,Flow Meter,m3//hr,#";

struct arrStructure stringTo = distrCsvMsgIntoStrgAry(dataRecived);

Serial.println(stringTo.arr[0]); Serial.println(stringTo.arr[1]); Serial.println(stringTo.arr[2]);

when i type this orders inside the void loop() the serial print :
confS
A
0

but if i use same 3 line within another function inside my Program, the serial returns empty values.

kindly help me to solve my problem

Thank you

3

How may comma separated values?
Using String this code is going to run out of, and/or fragment, memory very fast.
An array of 100 strings is huge for a start.

Best to use fixed sized buffers and strtok() function.

4

Duplicate topics merged to preserve replies

Thanks for owning up to the duplicate

5

hello, thanks pcbbc i will redefine the array with 15 Strings,

Sorry about post duplication, i deleted the first post on the sport but it didn't then i've made a report to solve this duplication.

this the code that i'm following it to make my Idea.

#include
using namespace std;

struct arrWrap {
int arr[100];
};

struct arrWrap fun()
{
struct arrWrap x;

x.arr[0] = 10;
x.arr[1] = 20;

return x;
}

int main()
{
struct arrWrap x = fun();
cout << x.arr[0] << " " << x.arr[1];
return 0;
}

Like this two function "struct arrWrap x = fun(); " "x.arr[1]; " works in the void loop Properly and returned the specific string that was called, but it returns empty values if i used them inside another function in the program.

6

Why not post the code that causes you problems so that we can help?

7

i just do this two function, to test the first step, my the problem solved, i was trying to define a empty list in class to fill it later in the program , and i was not give a size for this list.

AnalogPin analogPins[10]; // analogue pin from 0 to 15
int analogIndex=0;
DigitalPin digitalPins[20]={}; // digital pin from 22 to 51
int digitalIndex=0;

after i get the size of two listes "10" and "20" it works.

but i have another problem with Serial.readStringUntil('#')

i tried to do this sketch before potting in the main program , the i try to send this phrase (confS,A0,150,-5,6,70000,#) from the arduino serial. but the program stack on the Serial.readStringUntil('#') .
this is my code

struct  arrStructure { 
 String arr[8];        // this array contain the number of substring in data sent from raspberry pi to arduino
};

int k=0;
void setup() {
  Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}

void loop() {
  // send data only when you receive data:

   readFromRaspberryPi();  
  
}

///////////////////////////////////////////////////////////////////// readFromRaspberryPi ////////////////////
String readFromRaspberryPi()
{  delay(1000);
 unsigned long recivingTimer=millis();
  if(Serial.available()>0)
  { delay(1000);
    String dataRecived = Serial.readStringUntil("#");
//    delay(10);Serial.println("test");
    while ((millis()-recivingTimer)<5000)
    { 
    
//    String dataRecived="confS,A0,150,-5,6,70000,#";       //test    
    delay(100);  
    Serial.println(dataRecived);               
    delay(100);
     if(Serial.readStringUntil("#")=="ok" )
      {
        if (dataRecived.startsWith("confS"))
         {
         }
         }
    }
  }
}
8

If you're using Python on your RPi, it would make things a lot simpler and more reliable if you used the compatible libraries: pySerialTransfer and SerialTransfer.h.

pySerialTransfer is pip-installable and cross-platform compatible. SerialTransfer.h runs on the Arduino platform and can be installed through the Arduino IDE's Libraries Manager.

9

yes thank you, i will try this library but i'm did start yet in raspberry pi software I'm trying to test this sketch using Arduino serial reading, so what is the problem with Serial.readStringUntil('#') in this sketch ??

i try to make this small program for testing and the Serial.readStringUntil('#') worked properly.

struct  arrStructure { 
    String arr[20]; 
};


void setup() 
{
 Serial.begin(9600);
 

}


////////////////////////////////////////// loop ////////////////////////
  void loop() 
{
  if(Serial.available()>0)
  {
    String dataRecived = Serial.readStringUntil("#");
    Serial.println(dataRecived);
  }
}
10

problem solved thank you,

the problem was because i declared a String function (readFromRaspberryPi()) and i don't return any thing yet from this function, when i turned it to void function the Serial.readStringUntil("#") function works normally.