exchanging data between two hc05 bluetooth modules
I think there is no simple answer for that. First you have to pair 2 HC-05 modules. To do so, you have to configure one HC-05 as slave, and other HC-05 as master.

Steps for SLAVE:


Be sure to select correct Baudrate in your Terminal Emulator (Arduino IDE or Terraterm etc.) for your module. There is no default baudrate... Different manufacturers set the baudrate on their HC-05's differently... 9600 and 38400 are good starting points.
Enter AT mode, by providing high level(3.3V or 5V) signal on KEY pin(PIO11)
Note the values of AT+PSWD?, AT+NAME? and AT+ADDR?(let's say 1111:22:123456) commands. You might set the password to 1234 for easy remembering. Issue AT+PSWD=0000...
Be sure to set the module to slave mode by issuing AT+ROLE=0 command.


Steps for MASTER:


Be sure to select correct Baudrate in your Terminal Emulator (Arduino IDE or Terraterm etc.) for your module. There is no default baudrate... Different manufacturers set the baudrate on their HC-05's differently... 9600 and 38400 are good starting points.
Enter AT mode, by providing high level(3.3V or 5V) signal on KEY pin(PIO11)
Reset the module to its original state by issuing AT+ORGL command.
Remove the previous parings(if any) by issuing AT+RMAAD command.
Set same password as slave by issuing AT+PASSWD=0000 command.
Change the role to master; AT+ROLE=1
Set connecting mode to any address it sees; AT+CMODE=1
Initialize the SPP profile lib ; AT+INIT
Be sure that you see the slave HC-05 module, AT+INQ command will list the modules you see.
Be sure that you see address of the slave module(1111:22:123456).
Last of all enter AT+LINK=1111,22,123456(note the commas).


With these steps you should exchange data...