Introduction to the C ++ Manual

There is no end to learning. I recently learned some knowledge about the C ++ manual and wrote two pieces of code. I hope someone will comment on it and point out the error or the location for improvement. in the process of writing, I encountered a lot of problems. If you don't want to ask for help, I am posting for help.

View the C ++ manual and view the online tutorials. however, I still don't understand many basic C ++ knowledge. you are learning. due to busy work, the learning progress is really poor, and I have made a lot of C ++ language basics. I learned a lot there. if you are planning to learn about the C ++ manual, join them.

 
 

  
  
# Include<Stdlib. h>
  
  
# Include<Stdio. h>
  
  
# Include<Errno. h>
  
  
# Include<String. h>
  
  
# Include<Netdb. h>
  
  
# Include<Sys/Types. h>
  
  
# Include<Netinet/In. h>
  
  
# Include<Sys/Socket. h>
  
  
# Include<Syslog. h>
  
  
# Include<Unistd. h>
  
  
# Include<Netinet/In. h>
  
  
# Include<Sys/Socket. h>
  
  
# Include<Arpa/Inet. h>
  
  
# Include<Errno. h>
  
  
# Include<Sys/Ipc. h>
  
  
# Include<Sys/Shm. h>
  
  
/* Create a genie process */
  
  
Int daemon_init (void)
  
  
{Pid_t pid;
  
  
If ((Pid=Fork())< 0) Return (-1 );
  
  
Else if (pid! = 0) exit (0);/* parent exit */
  
  
/* Child continues */
  
  
Setsid ();/* become session leader */
  
  
Chdir ("// tmp");/* change working directory */
  
  
Umask (0);/* clear file mode creation mask */
  
  
Close (0);/* close stdin */
  
  
Close (1);/* close stdout */
  
  
Close (2);/* close stderr */
  
  
Return (0 );}
  
  
/* Read file data */
  
  
Void myread (char * buff)
  
  
{
  
  
Char buf [1024];
  
  
FILE * fp;
  
  
Fp=Fopen("/Proc/net/dev", "r ");
  
  
If (! Fp)
  
  
{
  
  
Perror ("fopen ");
  
  
Exit (2 );
  
  
}
  
  
Fgets (buf, 1024, fp );
  
  
Fgets (buf, 1024, fp );
  
  
Fgets (buf, 1024, fp );
  
  
Fgets (buf, 1024, fp );
  
  
Fscanf (fp, "% s", buf);/* read from the third row */
  
  
Snprintf (buff, 100, "% s", buf );
  
  
Fclose (fp );
  
  
Printf ("% s \ n", buf );
  
  
}
  
  

  
  
Int main (int argc, char * argv [])
  
  
{
  
  
Int sockfd, new_fd;
  
  
Struct sockaddr_in server_addr;
  
  
Struct sockaddr_in client_addr;
  
  
Int sin_size, portnumber;
  
  
Char hello [2, 1024];
  
  
/* The server starts to establish the socket descriptor */
  
  
If ((Sockfd=Socket(AF_INET, SOCK_STREAM, 0) =-1)
  
  
{
  
  
Printf ("Socket error: % s \ n \ a", strerror (errno ));
  
  
Exit (1 );
  
  
}
  
  
/* Fill in the sockaddr_in structure on the server */
  
  
Bzero (& server_addr, sizeof (struct sockaddr_in ));
  
  
Server_addr.sin_family=AF_INET;
  
  
Server_addr.sin_addr.s_addr=Inet_addr("Local IP Address ");
  
  
Server_addr.sin_port=Htons(10240);/* convert the port number to the network byte order */
  
  
/* Bind the sockfd descriptor */
  
  
If (bind (sockfd, (struct sockaddr *) (& server_addr), sizeof (struct sockaddr) =
  
  
-1)
  
  
{
  
  
Printf ("Bind error: % s \ n \ a", strerror (errno ));
  
  
Exit (1 );
  
  
}
  
  
/* Listen to the sockfd descriptor */
  
  
If (listen (sockfd, 5) =-1)/* 5 indicates the maximum number of requests in the Request queue */
  
  
{
  
  
Printf ("Listen error: % s \ n \ a", strerror (errno ));
  
  
Exit (1 );
  
  
}
  
  
While (1)
  
  
{
  
  
/* Server blocking until the Client Program establishes a connection */
  
  
Sin_size=Sizeof(Struct sockaddr_in );
  
  
If ((New_fd=Accept(Sockfd, (struct sockaddr *) (& client_addr), & sin_size
  
  
) =-1)
  
  
{
  
  
Printf ("Accept error: % s \ n \ a", strerror (errno ));
  
  
Exit (1 );
  
  
}
  
  
/* Inet_ntoa is used to convert a 32-bit Ipv4 address to a corresponding dot-decimal number string */
  
  
Printf ("Server get connection from % s \ n", inet_ntoa (client_addr.sin_addr ));
  
  
/* Send the content of the hello character array to the client */
  
  
Myread (hello );
  
  
If (write (new_fd, hello, strlen (hello) =-1)
  
  
{
  
  
Printf ("Write Error: % s \ n", strerror (errno ));
  
  
Exit (1 );
  
  
}
  
  
/* The communication has ended */
  
  
Close (new_fd );
  
  
}/* At the end of while */
  
  
Close (sockfd );
  
  
Exit (0 );
  
  
}
 
 

1. Differences between standard input implementation methods in C and C ++
2. How does the C ++ compiler allocate storage space for Const constants?
3. Basic Conception and method of C ++ Class Library Design
4. Several Methods for converting C ++ Language
5. How to better compile C ++ code