Theoretical Basis of set Interface Programming: TCP shot-back client program

Main function:

# Include "  Unp. h  " 

 Int Main ( Int Argc, Char ** Argv)
{
 Int Sockfd;
 Struct Sockaddr_in servaddr;

 If (Argc! = 2 )
Err_quit ("  Usage: tcpcli <IPaddress>  " );

 /*  Socket function prototype: int socket (INT family, int type, int Protocol); When protocol is 0
To select the default value for the combination of family and type. Refer to section 4.2,  */ 
Sockfd = socket (af_inet, sock_stream, 0 );

Bzero (& servaddr, Sizeof (Servaddr ));
Servaddr. sin_family = af_inet;
 /* Consider the mutual conversion between host byte order and network byte. Refer to section 3.4  */ 
Servaddr. sin_port = htons (serv_port );
 /*  Address Conversion Function inet_ton (INT, const char *, void *): converts an IPv4 address in decimal format to a 32-bit binary IPv4 address. Section 3.7  */ 
Inet_ton (af_inet, argv [ 1 ], & Servaddr. sin_addr );

 /*  Establish a connection with the server  */ 
Connect (sockfd, (Sa *) & servaddr, Sizeof (Servaddr ));

Str_cli (stdin, sockfd ); /*  Do it all  */ 

Exit ( 0 );
}

Str_cli functions:

This function completes the customer processing cycle: reads a line of text from the standard input, writes it to the server, reads the server's response to the line of text, and writes the response row to the standard output.

# Include "  Unp. h  " 

 Void 
Str_cli (File * FP, Int Sockfd)
{
Char Sendline [maxline], recvline [maxline];

 /*  Fgets reads a line of text  */ 
 While (Fgets (sendline, maxline, FP )! = NULL ){
 /*  Send this line of text to the server  */ 
Writen (sockfd, sendline, strlen (sendline ));

 /*  Readline reads the echo row from the server  */ 
If (Readline (sockfd, recvline, maxline) = 0 )
Err_quit ( "  Str_cli: Server terminated prematurely  " );
 /*  Fputs writes the echo row to the standard output.  */ 
Fputs (recvline, stdout );
}
}