Summary - Networking

Combine TCP client/server and Asio to write an echo server.

Summary: the echo server concept

In this summary we combine the socket, TCP client/server and Boost.Asio concepts in an echo server idea. An echo server sends back exactly what the client sends; it is the classic first example of network programming.

An echo server follows these steps: create a socket (socket), bind to a port (bind), wait for connections (listen), accept a client (accept), receive data (recv), send the same data back (send). With Boost.Asio these steps are done asynchronously. This lesson puts the basic socket and Asio setup together; the real echo logic comes in later projects.

Exercise Write the echo server skeleton

Add #include <sys/socket.h> and #include <boost/asio.hpp>. Create a TCP socket with int sock = socket(AF_INET, SOCK_STREAM, 0);. Define boost::asio::io_context io;. Print std::cout << "Echo ready";.

Show example solution

#include <iostream>
#include <sys/socket.h>
#include <boost/asio.hpp>

int main() {
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    boost::asio::io_context io;
    std::cout << "Echo ready";
    return 0;
}

Test yourself

Complete the socket call

int sock = ____(AF_INET, SOCK_STREAM, 0);

Show answer

int sock = socket(AF_INET, SOCK_STREAM, 0);

What does an echo server do?
- It compresses the data
- It deletes the data
- It encrypts the data
- It sends the data back unchanged
Show answer

It sends the data back unchanged — An echo server sends received data back unchanged.
Match the step to its role

socket()

Creates a socket
bind()

Binds to a port
listen()

Waits for connections
accept()

Accepts a client

Next lesson: Defining concepts

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies