Converting Int to String without conversion in ASCII

[mirage]

I am trying to convert a int variable into a string one, but the String() function is converting it to ASCII. So if I want to convert 255 to "255" I am getting "66" instead. I read that itoa should be able to do that, but when I try itoa(255,buffer,10); it still gives me 66.

In a JSON file I have a bunch of data that looks like this:

{ "0": [intValue, intValue, intValue, intValue, intValue, intValue, intValue, intValue],
"1": [intValue, intValue, intValue, intValue, intValue, intValue, intValue, intValue],
"2": [intValue, intValue, intValue, intValue, intValue, intValue, intValue, intValue],
...
...
...
"3000": [intValue, intValue, intValue, intValue, intValue, intValue, intValue, intValue]
}

I am choosing a random number from 0 to 3000 and trying to convert that to string to be able to extract the corresponding data using doc[].as<JsonArray>()

int random_number = random(3000);
JsonArray current_neighbors = doc[random_number].as<JsonArray>();

This is how my function looks like:

void Neighbors() {
    char current_char;
    int random_number = random(256);
    Serial.println("random_number");
    Serial.println(random(256));
    char current_number[20];
    itoa(random_number,current_number,DECIMAL_BASE);  
    Serial.println("current_number");
    Serial.println(current_number);
    File neighbors_file;
    neighbors_file = SD.open("NBHD.txt"); // Make sure the file name has max 8 characters
    char json_text[neighbors_file.size()];     
    unsigned int string_index = 0;
    StaticJsonDocument<capacity> doc;
    if (neighbors_file) {
    // read from the file until there's nothing else in it:
      while (neighbors_file.available()) {
        current_char = neighbors_file.read();
        json_text[string_index] = current_char;
        string_index++;
        json_text[string_index] = '\0';
      }
    DeserializationError error = deserializeJson(doc, json_text);

    if (error) {
      Serial.print(F("deserializeJson() failed: "));
      Serial.println(error.f_str());
      return;
    }

    JsonArray current_neighbors = doc[current_number].as<JsonArray>();
    Serial.println("Neighbors");
    for(JsonVariant v : current_neighbors) {
      Serial.println(v.as<int>());
     }
    neighbors_file.close();
}
}

And this is what I get:

[Danois90]

You do not provide any actual code, so it is not easy to help. Look at this - if it does not work, you are doing something wrong.

[ToddL1962]

@mirage

I am trying to convert a int variable into a string one, but the String() function is converting it to ASCII. So if I want to convert 255 to "255" I am getting "66" instead. I read that itoa should be able to do that, but when I try itoa(255,buffer,10); it still gives me 66.

Works for me:

void setup() {
  char buffer[4];
  Serial.begin(115200);
  itoa(255,buffer,10);
  Serial.println(buffer);
}

void loop() {
}

Must be a problem in the code you didn't post.

[mirage]

I added my code to the post if that helps. Thank you!

[Danois90]

Which board are you using? The line "char json_text[neighbors_file.size()]" does not allow null-termination of the contents. It should also be possible to do a single line read with "file.read(buffer, file.size())".

EDIT: How large is the file you are reading? With 3000 lines and multiple entries on each line It may very well exceed the available memory..

[mirage]

I'm using Teensy 4.1. Right now I am only using a subset of the file so only 255 lines and I updated the capacity based on what ArduinoJson Assist suggested for this file.

[Whandall]

@mirage

    int random_number = random(256);
    Serial.println("random_number");
    Serial.println(random(256));

Don't you think that the printed value should match the internally used one?
Printing a new random number does not make sense to me.

[mirage]

That's that I meant to do
They are equal now. Thanks