一个简单的C语言的socket服务器和客户端程序
程序很简单，windows环境下的，客户端和服务器程序都在本机运行，在客户端输入发送给服务器的字符串，服务器收到字符串后会打印出来，同时与"abc"比较，与"abc"相同就会返给客户端，输入的是正确的，不同会告诉客户端输入时错误的。客户端程序：client.cpp
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 2048
charszServer,
szMessage;
intiPort = DEFAULT_PORT;
int main()
{
WSADATA wsd;
SOCKET sClient;
char szBuffer;
int ret;
struct sockaddr_in server;
struct hostent *host = NULL;
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
printf("Failed to load Winsock library!\n");
return 1;
}
printf("Enter a string to send to server:\n");
gets(szMessage);
// Create the socket, and attempt to connect to the server
sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sClient == INVALID_SOCKET)
{
printf("socket() failed: %d\n", WSAGetLastError());
return 1;
}
server.sin_family = AF_INET;
server.sin_port = htons(iPort);
server.sin_addr.s_addr = inet_addr("127.0.0.1");
if (connect(sClient, (struct sockaddr *)&server,
sizeof(server)) == SOCKET_ERROR)
{
printf("connect() failed: %d\n", WSAGetLastError());
return 1;
}
// Send and receive data
ret = send(sClient, szMessage, strlen(szMessage), 0);
if (ret == SOCKET_ERROR)
{
printf("send() failed: %d\n", WSAGetLastError());
}
else{
printf("Send '%s' \n", szMessage);
ret = recv(sClient, szBuffer, DEFAULT_BUFFER, 0);
if (ret == SOCKET_ERROR){
printf("recv() failed: %d\n", WSAGetLastError());
}
else{
szBuffer = '\0';
printf("RECV: '%s'\n",szBuffer);
}
}
closesocket(sClient);
WSACleanup();
return 0;
}服务器程序:server.cpp
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 4096
int iPort = DEFAULT_PORT;
char szAddress;
DWORD WINAPI ClientThread(LPVOID lpParam)
{
SOCKET sock=(SOCKET)lpParam;
char szBuff;
int ret;
while(1)
{
ret = recv(sock, szBuff, DEFAULT_BUFFER, 0);
if (ret == 0)
break;
else if (ret == SOCKET_ERROR)
{
printf("recv() failed: %d\n", WSAGetLastError());
break;
}
szBuff = '\0';
printf("RECV: '%s'\n", szBuff);
if(strcmp(szBuff,"abc")==0){
memcpy(szBuff,"Send the correct string!",25);
}
else{
memcpy(szBuff,"Send the wrong string!",23);
}
ret = send(sock, szBuff, strlen(szBuff), 0);
if (ret == SOCKET_ERROR){
printf("send() failed: %d\n", WSAGetLastError());
}
}
return 0;
}
int main()
{
WSADATA wsd;
SOCKET sListen,
sClient;
int iAddrSize;
HANDLE hThread;
DWORD dwThreadId;
struct sockaddr_in local,
client;
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
printf("Failed to load Winsock!\n");
return 1;
}
// Create our listening socket
sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
if (sListen == SOCKET_ERROR)
{
printf("socket() failed: %d\n", WSAGetLastError());
return 1;
}
local.sin_addr.s_addr = htonl(INADDR_ANY);
local.sin_family = AF_INET;
local.sin_port = htons(iPort);
if (bind(sListen, (struct sockaddr *)&local,
sizeof(local)) == SOCKET_ERROR)
{
printf("bind() failed: %d\n", WSAGetLastError());
return 1;
}
listen(sListen, 8);
// In a continous loop, wait for incoming clients. Once one
// is detected, create a thread and pass the handle off to it.
while (1)
{
iAddrSize = sizeof(client);
sClient = accept(sListen, (struct sockaddr *)&client,
&iAddrSize);
if (sClient == INVALID_SOCKET)
{
printf("accept() failed: %d\n", WSAGetLastError());
break;
}
printf("Accepted client: %s:%d\n",
inet_ntoa(client.sin_addr), ntohs(client.sin_port));
hThread = CreateThread(NULL, 0, ClientThread,
(LPVOID)sClient, 0, &dwThreadId);
if (hThread == NULL)
{
printf("CreateThread() failed: %d\n", GetLastError());
break;
}
CloseHandle(hThread);
}
closesocket(sListen);
WSACleanup();
return 0;
}
作为服务器，你要绑定【bind】到本地的IP地址上进行监听【listen】，但是你的机器上可能有多块网卡，也就有多个IP地址，这时候你要选择绑定在哪个IP上面，如果指定为INADDR_ANY，那么系统将绑定默认的网卡【即IP地址】。
作为客户端，你要连接【connect】到远端的服务器，也是要指定远端服务器的（ip, port）对。
当然，在这种情况下，不可能将IP地址指定为INADDR_ANY，系统会疯掉的。
Server：
#include <winsock2.h>
#pragma comment(lib, "WS2_32.lib")
#include <stdio.h>
void main()
{
WORD wVersionRequested;//版本号
WSADATA wsaData;
int err;
wVersionRequested = MAKEWORD(2, 2);//2.2版本的套接字
//加载套接字库,如果失败返回
err = WSAStartup(wVersionRequested, &wsaData);
if (err != 0)
{
return;
}
//判断高低字节是不是2,如果不是2.2的版本则退出
if (LOBYTE(wsaData.wVersion) != 2 ||
HIBYTE(wsaData.wVersion) != 2)
{
return;
}
//创建流式套接字,基于TCP(SOCK_STREAM)
SOCKET socSrv = socket(AF_INET, SOCK_STREAM, 0);
//Socket地址结构体的创建
SOCKADDR_IN addrSrv;
addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY);//转换Unsigned long型为网络字节序格
addrSrv.sin_family = AF_INET;//指定地址簇
addrSrv.sin_port = htons(6000);
//指定端口号,除sin_family参数外,其它参数都是网络字节序,因此需要转换
//将套接字绑定到一个端口号和本地地址上
bind(socSrv, (SOCKADDR*)&addrSrv, sizeof(SOCKADDR));//必须用sizeof，strlen不行
listen(socSrv, 5);
SOCKADDR_IN addrClient;//字义用来接收客户端Socket的结构体
int len = sizeof(SOCKADDR);//初始化参数,这个参数必须进行初始化，sizeof
//循环等待接受客户端发送请求
while (1)
{
//等待客户请求到来；当请求到来后，接受连接请求，
//返回一个新的对应于此次连接的套接字（accept）。
//此时程序在此发生阻塞
SOCKET sockConn = accept(socSrv, (SOCKADDR*)&addrClient, &len);
char sendBuf;
sprintf(sendBuf, "Welcome %s to JoyChou",
inet_ntoa(addrClient.sin_addr));//格式化输出
//用返回的套接字和客户端进行通信
send(sockConn, sendBuf, strlen(sendBuf)+1, 0);//多发送一个字节
//接收数据
char recvBuf;
recv(sockConn, recvBuf, 100, 0);
printf("%s\n", recvBuf);
closesocket(sockConn);
}
}
Client：
#include <winsock2.H>
#pragma comment(lib, "Ws2_32.lib")
#include <stdio.h>
#include <string.h>
void main()
{
WORD wVersionRequested;
WSADATA wsaData;
int err;
wVersionRequested = MAKEWORD( 2, 2 );
err = WSAStartup( wVersionRequested, &wsaData );
if ( err != 0 ) {
return;
}
if ( LOBYTE( wsaData.wVersion ) != 2 ||
HIBYTE( wsaData.wVersion ) != 2 )
{
WSACleanup( );
return;
}
SOCKET socketClient = socket(AF_INET, SOCK_STREAM, 0);
SOCKADDR_IN addrSrv;
addrSrv.sin_family = AF_INET;
addrSrv.sin_port = htons(6000);
addrSrv.sin_addr.S_un.S_addr = inet_addr("192.168.1.101");//服务器端的IP地址
connect(socketClient, (SOCKADDR *)&addrSrv, sizeof(SOCKADDR));
char recvBuf;
char sendBuf[] = "This is Joychou";
recv(socketClient, recvBuf, 256, 0);
printf("%s\n", recvBuf);
send(socketClient, sendBuf, strlen(sendBuf) + 1, 0);
closesocket(socketClient);
WSACleanup();
}
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