arduino mega serial talking with strings

hi all, i am trying to communicate a serial device (pic 12f) with arduino mega. i connected device to serialport3. when i send command 'g' to serialport3, device blinks a led and sends a sentence like "ok now\n\r". i send 'g' command to the device by sending 'a' command to arduino. also i want to see the device's reply from arduino serial monitor. i see the led blinks but i couldn't read the sentence. i am trying to modify serial event skecth, where problem can be?

String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete

inputString.reserve(200);
void setup() {

  Serial.begin(9600);
  Serial3.begin(9600);
  // reserve 200 bytes for the inputString:
  inputString.reserve(200);
}
void loop() {
  /*  
   if (Serial.available()) 
   {
   char ser = Serial.read();
   if(ser == 'a'){
   Serial3.write('g');
   
   }
  
   }
   }
   */
  if (stringComplete) {
    Serial.println(inputString); 
    // clear the string:
    inputString = "";
    stringComplete = false;
  }
}

void serialEvent() {
  while (Serial3.available()) {
    // get the new byte:
    char inChar = (char)Serial3.read(); 
    // add it to the inputString:
    inputString += inChar;
    // if the incoming character is a newline, set a flag
    // so the main loop can do something about it:
    if (inChar == '\n') {
      stringComplete = true;
    } 
  }
}

use insert code.

Moderator edit: Dummy code tags corrected.

arduino mega serial talking with strings

String inputString = "";         // a string to hold incoming data

There is a world of difference between a string and a String. The sooner that you learn what that one little letter difference means, the better.

i send 'g' command to the device by sending 'a' command

I call by brother Tom by the name of George...

  /*  
   if (Serial.available()) 
   {
   char ser = Serial.read();
   if(ser == 'a'){
   Serial3.write('g');
   
   }
  
   }
   }
   */

Thanks for posting all this... Is your delete key broken?

  // reserve 200 bytes for the inputString:
  inputString.reserve(200);

You need to reserve 200 characters to hold a one letter command? Are you serious?

but i couldn't read the sentence.

What sentence? The only code to output anything is commented out.