Client-Server Socket Programming Example in C++

This example demonstrates a simple client-server communication using sockets in C++. The server listens for connections from clients, receives messages from clients, and echoes back a response. The client connects to the server, sends a message passed as a command-line argument, and displays the echoed response from the server.

Files Included

• client.cpp: Client application that connects to a server, sends a message passed as a command-line argument, and displays the server's response.
• server.cpp: Server application that binds to a specified port, listens for incoming client connections, receives messages from clients, and echoes a response.

How to Run

Prerequisites

• C++ compiler (e.g., clang++)

Steps to Compile and Run

1. Pre-compilationn Before compiling, modify the port_num variable in both client.cpp and server.cpp to ensure they are set to the same port number. By default, we'll use 9093 as an example.

2. Compiling the program

   Open a terminal/command prompt window and navigate to the directory containing server.cpp and client.cpp.

   //compile the program for server
   clang++ server.cpp -o server
   
   //compile the program for client
   clang++ client.cpp -o client

3. Running the program Open a terminal and run the server program

   ./server

   Open another terminal and run the client program

   ./client "Your message here"

Possible Issues

1. Port already taken

   If you encounter connection issues, such as failing to bind the server socket due to the port already being taken or busy, follow these steps to resolve the issue:

   Open a terminal/command prompt window and run the following command to check if the port specified (port_num) is already in use: if the command returns output (i.e., it's not empty), it indicates that the port is already taken.

   ss -tuln | grep port_num

   To solve this issue, you need to modify the port_num variable in both client.cpp and server.cpp to another available port number.