using 3 sockets with files

We will create 3 sockets two Servers and one Client : ServerA and ServerB and Client

My Problem is that I don't know how to use files in sockets and perl and also I don't know how to create a communication between 3 Sockets
I know only with Client/Server

Is there anyone who can help me in doing this.

This is the Instructions :

The Client will send the string containing his name and his credit card number (Exemple : "Carl, 5321456855741") and wait.
This String will be sent to ServerA with a communication protocol between Client and ServerA.

Then ServerA will modify the information and make it in this form "Carl-5321456855741" then send it to ServerB.

ServerB will verify if the informtion is correct or not by searching in a text file (created already and contain a list of names and Credit card numbers in this
form "Name-CardNumber-Amount" in each line) :

*) If it's correct (existing in the text file) ServerB will reply "Welcome $Name you have $Amount in your account" to ServerA and ServerA will send the
same message received from ServerB to Client.

*) If it's not correct (not existing in the text file) ServerB will reply "Sorry your informations is incorrect" to ServerA and ServerA will send the
same message received from ServerB to Client.

Hello arekik,

this is a French-speaking forum, you should ask questions in French.

In addition, this looks like homework. Please do not expect us to do your homework for you, that would be a very bad service to you. We can help you if you encounter some difficulties while trying by yourself to solve your problem, we will not do the work for you.

________

En français, brièvement: c'est un forum francophone, les questions doivent être posées en français. De plus il s'agit manifestement d'un devoir scolaire, nous ne ferons pas ce devoir à la place du demandeur. Ce serait d'ailleurs lui rendre un bien mauvais service. Nous pouvons aider s'il rencontre des difficultés, pas faire son devoir à sa place.