采用的是VC2008,控制臺應用程序，使用UDP編寫。

1、服務端代碼

//UDPServer.cpp

#include <WinSock2.h>  
#include <stdio.h>  
  
#define SERVERPORT 6000 //服務端口號  
  
#pragma comment(lib, "WS2_32.lib");  
  
int main(int argc, char *argv[])  
{  
    //加載套接字庫  
    WORD wVersionRequested;  
    WSADATA wsaData;  
    int err;  
  
    wVersionRequested 
 
= MAKEWORD( 2, 2 );  
      
    err = WSAStartup( wVersionRequested, &wsaData );  
    if ( err != 0 ) {  
        /* Tell the user that we could not find a usable */  
        /* WinSock DLL.                                  */  
        return -1;  
    }  
  
    /* Confirm that the WinSock DLL supports 2.2.
 
*/  
    /* Note that if the DLL supports versions greater    */  
    /* than 2.2 in addition to 2.2, it will still return */  
    /* 2.2 in wVersion since that is the version we      */  
    /* requested.                                        */  
  
    if ( LOBYTE( wsaData.wVersion ) != 2 ||  
        HIBYTE( wsaData.wVersion ) 
 
!= 2 ) {  
            /* Tell the user that we could not find a usable */  
            /* WinSock DLL.                                  */  
            WSACleanup( );  
            return -1;   
    }  
  
    /* The WinSock DLL is acceptable. Proceed. */  
    //創建套接字  
    SOCKET sockServer = socket(AF_INET, SOCK_DGRAM, 0);  
    if (INVALID_SOCKET == sockServer)  
    {  
        printf("socket() called failed! The error code is: %d\n", WSAGetLastError());  
        return -1;  
    }  
    else  
    {  
        printf("socket() called succesful!\n");  
    }  
      
    //服務器端  
    SOCKADDR_IN addrServer;  
    addrServer.sin_addr.S_un.S_addr = htonl(INADDR_ANY);  
    addrServer.sin_family = AF_INET;  
    addrServer.sin_port = htons(SERVERPORT);  
  
    //綁定套接字  
    err = bind(sockServer, (SOCKADDR*)&addrServer, sizeof(SOCKADDR));  
    if (SOCKET_ERROR == err)  
    {  
        printf("bind() called failed! The error code is: %d\n", WSAGetLastError());  
        return -1;  
    }  
    else  
    {  
        printf("bind() called successful!\n");  
    }  
  
    //等待並接收數據  
    SOCKADDR_IN addrClient;//用於接收發送端的地址信息  
    int len = sizeof(SOCKADDR);  
    char recvBuf[100];  
    recvfrom(sockServer, recvBuf, 100, 0, (SOCKADDR*)&addrClient, &len);  
    //打印接收到的數據  
    printf("receive data:%s from client [%s,%d]", recvBuf, inet_ntoa(addrClient.sin_addr), addrClient.sin_port);  
      
    //關閉套接字  
    closesocket(sockServer);  
      
    //終止套接字庫的使用  
    WSACleanup();  
      
    return 0;  
}  

2、客戶端代碼

//UDPClient.cpp

#include <WinSock2.h>  
#include <stdio.h>  
  
#define SERVERPORT 6000 //服務端口號  
  
#pragma comment(lib, "WS2_32.lib");  
  
int main(int argc, char *argv[])  
{  
    //加載套接字庫  
    WORD wVersionRequested;  
    WSADATA wsaData;  
    int err;  
  
    wVersionRequested = MAKEWORD( 2, 2 );  
  
    err = WSAStartup( wVersionRequested, &wsaData );  
    if ( err != 0 ) {  
        /* Tell the user that we could not find a usable */  
        /* WinSock DLL.                                  */  
        return -1;  
    }  
  
    /* Confirm that the WinSock DLL supports 2.2.*/  
    /* Note that if the DLL supports versions greater    */  
    /* than 2.2 in addition to 2.2, it will still return */  
    /* 2.2 in wVersion since that is the version we      */  
    /* requested.                                        */  
  
    if ( LOBYTE( wsaData.wVersion ) != 2 ||  
        HIBYTE( wsaData.wVersion ) != 2 ) {  
            /* Tell the user that we could not find a usable */  
            /* WinSock DLL.                                  */  
            WSACleanup( );  
            return -1;   
    }  
      
    //創建套接字  
    SOCKET sockClient = socket(AF_INET, SOCK_DGRAM, 0);  
    if (INVALID_SOCKET == sockClient)  
    {  
        printf("socket() called failed! The error code is: %d\n", WSAGetLastError());  
        return -1;  
    }  
    else  
    {  
        printf("socket() called succesful!\n");  
    }  
  
    SOCKADDR_IN addrServer;  
    addrServer.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");  
    addrServer.sin_family = AF_INET;  
    addrServer.sin_port = htons(SERVERPORT);  
      
    //發送數據  
    err = sendto(sockClient, "Hello", strlen("Hello")+1, 0, (SOCKADDR*)&addrServer, sizeof(SOCKADDR));  
    if (SOCKET_ERROR == err)  
    {  
        printf("sendto() called failed! The error code is: %s\n", WSAGetLastError());  
        return -1;  
    }  
    else  
    {  
        printf("sendto() called successful!\n");  
    }  
  
    //關閉套接字  
    closesocket(sockClient);  
  
    //終止套接字庫的使用  
    WSACleanup();  
  
    return 0;  
}  

註意：上面兩部分代碼中的

#pragma comment(lib, "WS2_32.lib"); 

可以刪除，而改為設置程序屬性，具體如下步驟：

　　server 和 client 都要"項目屬性"--->"配置屬性"----> "鏈接"----> "輸入" --->"附加依賴項"中添加"ws2_32.lib"

先啟動服務端UDPServer程序，再啟動客戶端UDPClient程序，運行結果如下：

服務端UDPServer

客戶端UDPClient

此時服務端UDPServer的結果會發生變化，會受到客戶端發送過來的數據，如下圖所示：

參考資料：

1、《VC++深入詳解》 第14章網絡編程 ，孫鑫主編

2、MSDN幫助文檔

VC++ UDP網絡控制臺程序