void setup() {
  char msg[16];
  long i = 12345678;

  // put your setup code here, to run once:
  Serial.begin(115200);

  dtostrf((float) (i/100) / 10.0, 2, 1, msg);
  Serial.println(msg);

}

void loop() {
  // put your main code here, to run repeatedly:

}