Zigbee Arduino Basics

Hello every one...

I am doing some basic practice on Arduino and Xbee, I need some help if there is someone who can put me on track.

Basically I want to make communication between two Arduinos through Xbee.

This is the sender node which is sending a Packet with a counter.

int count = 1;
void setup() {
Serial.begin(9600);
}

void loop() {
  Serial.print("Packet (");
  Serial.print(count);
  Serial.print(") ");
  Serial.println("sent.");
  delay(2000);
  count ++;
}

And the receiver is getting that packet correctly which is given below

char inc;

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

void loop() {
    if (Serial.available()) {
    inc = Serial.read();
    Serial.print(inc); 
  }
}

Now what I want the receiving the node that when it reads the whole packet it should send back an acknowledgment to its sender. What should I do now. What should I further add to this two programs.

Please take me out of this tension as soon as possible... >:(

If you want to make the receiver send back an acknowledgement, it would have to contain some code that looks very much like your sender program.

If you want reliable Serial communication, read Basic Serial Input

I want that sender wait for some time for the ack from receiver before sending the next message. if ack still not received in the wait time, it should send the next.