How do I make a character array scanner properly?

Question

I start with this:

char delay_chars[10];

then I have a stream of incoming characters that I need to assign like this:

['I', ' ', 'l', 'o', 'v', 'e', ' ', 'p', 'i', 'e']

I can do that, but then more characters come in so I need it like this:

[' ', 'l', 'o', 'v', 'e', ' ', 'p', 'i', 'e', ' ']
['l', 'o', 'v', 'e', ' ', 'p', 'i', 'e', ' ', 'a']
['o', 'v', 'e', ' ', 'p', 'i', 'e', ' ', 'a', 'n']
['v', 'e', ' ', 'p', 'i', 'e', ' ', 'a', 'n', 'd']
['e', ' ', 'p', 'i', 'e', ' ', 'a', 'n', 'd', ' ']
[' ', 'p', 'i', 'e', ' ', 'a', 'n', 'd', ' ', 'c']
['p', 'i', 'e', ' ', 'a', 'n', 'd', ' ', 'c', 'a']
['i', 'e', ' ', 'a', 'n', 'd', ' ', 'c', 'a', 'k']
['e', ' ', 'a', 'n', 'd', ' ', 'c', 'a', 'k', 'e']

You get the idea. I don't know how I can remove the first character of a char array (like I do with a String, remove(0, 1)) and I don't know how to add a new element at the end.

If I had to guess, I'd make a loop that will reassign the index of each character one step back or something like that but I'm not sure if that's how I should do it.

Answer 1

If I had to guess, I'd make a loop that will reasign the index of each character one step back or something like that but I'm not sure if that's how I should do it.

Yep, that's pretty much it...

Here's how I do it:

char data[10];

if (Serial.available()) {
    char inch = Serial.read();
    for (int i = 0; i < 9; i++) {
        data[i] = data[i+1];
    }
    data[9] = inch;
}

Every incoming character gets added to the end of the array after everything else has been shuffled down one place.

Answer 2

You can use SerialTransfer.h to automatically packetize and parse your data for inter-Arduino communication without the headace. The library is installable through the Arduino IDE and includes many examples.

Here are the library's features:

This library:

• can be downloaded via the Arduino IDE's Libraries Manager (search "SerialTransfer.h")
• works with "software-serial" libraries
• is non blocking
• uses packet delimiters
• uses consistent overhead byte stuffing
• uses CRC-8 (Polynomial 0x9B with lookup table)
• allows the use of dynamically sized packets (packets can have payload lengths anywhere from 1 to 255 bytes)
• can transfer bytes, ints, floats, and even structs!!

Example TX Arduino Sketch:

#include "SerialTransfer.h"

SerialTransfer myTransfer;

void setup()
{
  Serial.begin(115200);
  Serial1.begin(115200);
  myTransfer.begin(Serial1);
}

void loop()
{
  myTransfer.txBuff[0] = 'h';
  myTransfer.txBuff[1] = 'i';
  myTransfer.txBuff[2] = '\n';

  myTransfer.sendData(3);
  delay(100);
}

Example RX Arduino Sketch:

#include "SerialTransfer.h"

SerialTransfer myTransfer;

void setup()
{
  Serial.begin(115200);
  Serial1.begin(115200);
  myTransfer.begin(Serial1);
}

void loop()
{
  if(myTransfer.available())
  {
    Serial.println("New Data");
    for(byte i = 0; i < myTransfer.bytesRead; i++)
      Serial.write(myTransfer.rxBuff[i]);
    Serial.println();
  }
  else if(myTransfer.status < 0)
  {
    Serial.print("ERROR: ");
    Serial.println(myTransfer.status);
  }
}

You can easily edit the above example code to transfer ['I', ' ', 'l', 'o', 'v', 'e', ' ', 'p', 'i', 'e'] instead of ['h', 'i', '\n'].