void setup()
{
  Serial.begin( 115200 );



  // Print and parse string

  const char numbers_str[] = "-110,-123,-177";

  Serial.print( "string = \"" );
  Serial.print( numbers_str );
  Serial.println( "\"" );

  const size_t max_numbers = 10;
  int numbers_int[ max_numbers ];
  size_t index = 0;

  while ( index < max_numbers )
  {
    static char *p1 = numbers_str;
    static char *p2;

    const int number = strtol( p1, &p2, 10 ); // Try parse a number at the actual position

    if ( p1 == p2 ) break; // Break loop if a number was not successfully parsed

    numbers_int[ index++ ] = number; // Store number

    if ( *p2 == '\0' ) break; // Break loop if the end of string is reached

    p1 = p2 + 1; // Set position after ',' to try parse another number
  }



  // Modify numbers

  for ( size_t i = 0; i < index; ++i )
  {
    numbers_int[ i ] *= 10;
  }



  // Build and print new string

  const size_t max_number_str_size = 7; // Size of "-32768" (min value of an int)
  char new_numbers_str[ max_numbers * max_number_str_size ];

  for ( size_t i = 0; i < index; ++i )
  {
    char number_str[ max_number_str_size ];
    itoa( numbers_int[ i ], number_str, 10 );
    strcat( new_numbers_str, number_str );

    if ( i < index - 1 )
    {
      strcat( new_numbers_str, "," );
    }
  }

  Serial.print( "string = \"" );
  Serial.print( new_numbers_str );
  Serial.println( "\"" );
}



void loop()
{
}