A simple network program source code for beginners

Here is a simple network program source code for beginners-Linux general technology-Linux programming and kernel information. Send new users a simple server and client code for them to learn.

Server Source Code:
# Include
# Include
# Include
# Include
# Include
# Include
# Include

# Deprecision MAX_LINE 100

Void my_fun (char * p)
{
If (p = NULL)
Return;

For (; * p! = '\ 0'; p ++)
If (* p> = 'A' & * p <= 'Z ')
* P = * p-'A' + 'a ';
}
Int main (void)
{
Struct sockaddr_in sin;
Struct sockaddr_in cin;
Int l_fd;
Int c_fd;
Socklen_t len;
Char buf [MAX_LINE];
Char addr_p [INET_ADDRSTRLEN];
Int port = 8000;
Int n;

Bzero (& sin, sizeof (sin ));
Sin. sin_family = AF_INET;
Sin. sin_addr.s_addr = INADDR_ANY;
Sin. sin_port = htons (port );
L_fd = socket (AF_INET, SOCK_STREAM, 0 );
Bind (l_fd, (struct sockaddr *) & sin, sizeof (sin ));
Listen (l_fd, 10 );
Printf ("waiting... \ n ");

While (1)
{
C_fd = accept (l_fd, (struct sockaddr *) & cin, & len );
N = read (c_fd, buf, MAX_LINE );
Inet_ntop (AF_INET, & cin. sin_addr, addr_p, sizeof (addr_p ));
Printf ("client ip is % s, port is % d \ n", addr_p, ntohs (cin. sin_port ));
Printf ("content is: % s \ n", buf );
My_fun (buf );
Write (c_fd, buf, n );
Close (c_fd );
}
If (close (l_fd) =-1)
{
Perror ("fail to close \ n ");
Exit (1 );
}
Return 0;
}