Simple TCP/IP echo client

This program demonstrates a simple TCP/IP client. It will connect to an echo server and echo a string the user types.

Programming Issues

This program illustrates the classic process for a TCP/IP client program. Summarised, it is as follows:

Create a socket with a call to socket()
Create and initialize a socket address structure with the address family (AF_INET here), the server's remote IP address, and the port the server is listening on.
Actively connect to the server by calling connect()
Communicate with the server, and (in this case) allow the server to perform the active close.

Usage

Launch a server process in the background (or find one already running) and run the program to connect to it:

[paul@localhost paul]$ ./echoserv 3357 &
[paul@localhost paul]$ ./echoclnt -a 127.0.0.1 -p 3357
Enter the string to echo: Echo me, please.
Echo response: Echo me, please.

[paul@localhost paul]$

Use the -a and -p switches to specify the remote IP address and port of the server.