The parent takes a message (from the command line), sends it to the child (through the pipe), and the child displays the message.
The program has just one argument on the command line (the message).
An example of the execution could be:
Prompt -> oneway hellothere
I am the parent. I sent the message: hellothere.
I am the child. I received the message: hellothere.
Attached program makes use of unnamed pipe, the one that is created using the "pipe" system call.