Create a program that accepts a list of host names on the command line. For example

./a.out yahoo.com slashdot.net

for each address, a child is spawned that attempts to connect to that address on port 80, and sends

"GET / HTTP/1.1 Host:

Connection: close "

through the socket. If it receives data in response (reading the socket results in more than 0 bytes read) it end with return code 0, otherwise it returns -1.

The parent waits for all processes to end then prints the total number of children that returned 0.