[Linux] applet: UDP The client transmits multiple strings to the server

Or the homework of the experiment ~

Total two files required, this is the client

1#include <stdio.h>2#include <sys/socket.h>3#include <arpa/inet.h>4#include <stdlib.h>5#include <string.h>6#include <unistd.h>7 8 #defineEchomax 2559 Ten intMainintargcChar*argv[]) { One     intsock; A     structsockaddr_in echoservaddr; -     structsockaddr_in fromaddr; -Unsigned ShortEchoservport; theUnsignedintfromsize; -     Char*Servip; -     Char*echostring; -     Charechobuffer[echomax+1]; +     intechostringlen=0; -     intRespstringlen; +     intI//For counting A  at     if(argc<3) { -printf"usage:%s <server ip> <echo port> [<echo words>]\n", argv[0]); -Exit1); -     } -  -SERVIP = argv[1]; in      -      for(i=3; i<argc;i++){ toEchostringlen = Echostringlen +strlen (Argv[i]); +     } -     if(Echostringlen >Echomax) theprintf"Echo Word too long.\n"); *  $Echoservport = Atoi (argv[2]);Panax Notoginseng  -     if((sock = socket (pf_inet, SOCK_DGRAM, IPPROTO_UDP) <0) theprintf"socket () failed.\n"); +memset (&AMP;ECHOSERVADDR,0,sizeof(ECHOSERVADDR)); Aechoservaddr.sin_family =af_inet; theECHOSERVADDR.SIN_ADDR.S_ADDR =inet_addr (SERVIP); +Echoservaddr.sin_port =htons (echoservport); -  $      for(i=3; i<argc;i++) { $echostring =Argv[i]; -         if(SendTo (Sock,echostring,strlen (echostring),0,(structSOCKADDR *) &echoservaddr,sizeof(ECHOSERVADDR))) !=strlen (echostring)) -printf"sendto () sent a different number of bytes than expected.\n"); the         } -     }WuyiEchobuffer[strlen (echostring)] =' /'; the Close (sock); -Exit0); Wu } -     

This is the server

#include <stdio.h>#include<sys/socket.h>#include<arpa/inet.h>#include<stdlib.h>#include<string.h>#include<unistd.h>#defineEchomax 255intMainintargcChar*argv[]) {    intsock; structsockaddr_in echoservaddr; structsockaddr_in echoclntaddr; unsignedintCliaddrlen; CharEchobuffer[echomax]; unsigned ShortEchoservport; intrecvmsgsize; intI//For counting    if(ARGC! =2) {printf ("Usage:%s <udp SERVER port>\n", argv[0]); Exit (1); } echoservport= Atoi (argv[1]); if(sock = socket (Pf_inet,sock_dgram,0)) <0) printf ("socket () failed.\n"); memset (&AMP;ECHOSERVADDR,0,sizeof(ECHOSERVADDR)); Echoservaddr.sin_family=af_inet; EchoServAddr.sin_addr.s_addr=htonl (Inaddr_any); Echoservaddr.sin_port=htons (Echoservport); if(Bind (sock, (structSOCKADDR *) &echoservaddr,sizeof(ECHOSERVADDR))) <0) printf ("bind () failed.\n");  for (;;) {Cliaddrlen=sizeof(ECHOCLNTADDR); if(Recvmsgsize = Recvfrom (Sock,echobuffer,strlen (Echobuffer),0,(structSOCKADDR *) &echoclntaddr,&cliaddrlen) <0) printf ("recvfrom () failed.\n"); printf ("Handling Client%s\n", Inet_ntoa (ECHOCLNTADDR.SIN_ADDR)); printf ("Message:");  for(i=0; i<recvmsgsize;i++) {printf ("%c", Echobuffer[i]); if(i== (recvmsgsize-1)) printf ("\ n"); }} printf ("\ n");}

Examples of Use:

For example, the string you want to transfer is Hello, world!

Then you need to run server first:

./server 1500

1500 is the port number (in fact, under the permission of ordinary users, using a >1024 port can be)

Then run client: (press ALT+F2 to switch to a new window to run)

./client 127.0.0.1-Hello, world!

Then alt+f1 back to the original window and you can see:

Handling client 127.0.0.1

Message:hello,

Handling client 127.0.0.1

message:world!

[Linux] applet: UDP The client transmits multiple strings to the server