socket的客户端，服务器范例

socket的客户端，服务器范例：


（一）范例一：


（1）服务器端：

#include<stdio.h>

 #include<stdlib.h>

 #include<string.h>

 #include<errno.h>

 #include<sys/types.h>

 #include<sys/socket.h>

 #include<netinet/in.h>



 #define MAXLINE 4096



 int main(int argc, char** argv)

 {

     int    listenfd, connfd;

     struct sockaddr_in     servaddr;

     char    buff[4096];

     int     n;



     if( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){

     printf("create socket error: %s(errno: %d)/n",strerror(errno),errno);

     exit(0);

     }



     memset(&servaddr, 0, sizeof(servaddr));

     servaddr.sin_family = AF_INET;

     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

     servaddr.sin_port = htons(6666);



     if( bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){

     printf("bind socket error: %s(errno: %d)/n",strerror(errno),errno);

     exit(0);

     }



     if( listen(listenfd, 10) == -1){

     printf("listen socket error: %s(errno: %d)/n",strerror(errno),errno);

     exit(0);

     }



     printf("======waiting for client's request======/n");

     while(1){

     if( (connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -1){

         printf("accept socket error: %s(errno: %d)",strerror(errno),errno);

         continue;

     }

     n = recv(connfd, buff, MAXLINE, 0);

     buff[n] = '/0';

     printf("recv msg from client: %s/n", buff);

     close(connfd);

     }



     close(listenfd);

 }

（2）客户端：

#include<stdio.h>

 #include<stdlib.h>

 #include<string.h>

 #include<errno.h>

 #include<sys/types.h>

 #include<sys/socket.h>

 #include<netinet/in.h>



 #define MAXLINE 4096



 int main(int argc, char** argv)

 {

     int    sockfd, n;

     char    recvline[4096], sendline[4096];

     struct sockaddr_in    servaddr;



     if( argc != 2){

     printf("usage: ./client <ipaddress>/n");

     exit(0);

     }



     if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){

     printf("create socket error: %s(errno: %d)/n", strerror(errno),errno);

     exit(0);

     }



     memset(&servaddr, 0, sizeof(servaddr));

     servaddr.sin_family = AF_INET;

     servaddr.sin_port = htons(6666);

     if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0){

     printf("inet_pton error for %s/n",argv[1]);

     exit(0);

     }



     if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){

     printf("connect error: %s(errno: %d)/n",strerror(errno),errno);

     exit(0);

     }



     printf("send msg to server: /n");

     fgets(sendline, 4096, stdin);

     if( send(sockfd, sendline, strlen(sendline), 0) < 0)

     {

     printf("send msg error: %s(errno: %d)/n", strerror(errno), errno);

     exit(0);

     }



     close(sockfd);

     exit(0);

 }

（3）分析：
上面的服务器使用的是迭代模式的，即只有处理完一个客户端请求才会去处理下一个客户端的请求，这样的服务器处理能力是很弱的，现实中的服务器都需要有并发处理能力！为了需要并发处理，服务器需要fork()一个新的进程或者线程去处理请求等。


---------------------
（二）范例二：
（1）服务器端：

// Server.cpp : Defines the entry point for the console application.

 //



 #include "stdafx.h"

 #include <Winsock2.h>



 #pragma comment(lib,"ws2_32.lib")



 #define  PORT_NUMBER 11234

 #define  MAX_BUF_SIZE 1024

 int _tmain(int argc, _TCHAR* argv[])

 {

WSADATA wSaData;

WORD dwSockVersion = MAKEWORD(2,2);

if (0 != WSAStartup(dwSockVersion,&wSaData)) //协商版本号

{

printf("Arrange Version Failure");

return -1;

}



SOCKET nSocket;

nSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); //创建TCP socket

if (INVALID_SOCKET == nSocket)

{

printf("invalid socket");

WSACleanup();

return -1;

}



sockaddr_in sa;

sa.sin_family = AF_INET;

sa.sin_addr.s_addr = inet_addr("127.0.0.1");

sa.sin_port = htons(PORT_NUMBER);//选择一个端口号



if (bind(nSocket,(sockaddr *)&sa,sizeof(sa)) < 0) //绑定

{

closesocket(nSocket);
 

return -1;

}

listen(nSocket,2);



sockaddr_in addr_client;

int nAddrLen = sizeof(addr_client);

while(TRUE)

{

//SOCKET nSock = accept(nSocket,(sockaddr *)&addr_client,&nAddrLen);

SOCKET nSock = accept(nSocket,NULL,NULL);

if (INVALID_SOCKET == nSock)

{

printf("failure to accept");

continue;

}



char tmp[MAX_BUF_SIZE] = {0};

char buf[MAX_BUF_SIZE] = {0};

strcpy(tmp,"this is server");

send(nSock, tmp, (int)strlen(tmp), 0);

int nRecv = recv(nSock, buf, MAX_BUF_SIZE, 0);

if (nRecv > 0)

{

printf("%s/n",buf);

}

closesocket(nSock);



return 0;

}



 }





 （2）客户端：

 // Client.cpp : Defines the entry point for the console application.

 //



 #include "stdafx.h"

 #include <Winsock2.h>



 #pragma comment(lib,"ws2_32.lib")



 #define  MAX_BUF_SIZE 1024

 #define  PORT_NUMBER 11234

 int _tmain(int argc, _TCHAR* argv[])

 {



WSADATA wSaData;

WORD dwSockVersion = MAKEWORD(2,2);

if (0 != WSAStartup(dwSockVersion,&wSaData)) //协商版本号

{

printf("Arrange Version Failure");

return -1;

}



SOCKET nSocket;

nSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); //创建TCP socket

if (INVALID_SOCKET == nSocket)

{

printf("invalid socket");

WSACleanup();

return -1;

}



sockaddr_in sa;

sa.sin_family = AF_INET;

sa.sin_addr.s_addr = inet_addr("127.0.0.1");

sa.sin_port = htons(PORT_NUMBER);

if ( 0 != connect( nSocket,( const SOCKADDR * )&sa, sizeof(sa) ) )

return -1;



char buf[MAX_BUF_SIZE] = {0};

char tmp[MAX_BUF_SIZE] = {0};

strcpy(tmp,"this is Client!");

int nRecv = 0;

nRecv = recv(nSocket, buf, MAX_BUF_SIZE, 0);

if (nRecv > 0)

{

printf("%s/n",buf);

send(nSocket, tmp, (int)strlen(tmp), 0);

}



closesocket(nSocket);

WSACleanup();



return 0;

 }