服务端：socket -> bind -> sento/recvfrom -> close
客户端: socket -> sendto/recvfrom -> close

服务端：

#include<WinSock2.h>
#include<iostream>
#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main(int argc, char * argv[]) {
    const int BUFSIZE = 1024;
    SOCKET      ServerSocket;
    SOCKADDR_IN ServerAddr;
    SOCKADDR_IN ClientAddr;
    WSADATA     wsaData;
    char        buf[BUFSIZE];
    int ret;
    
    if ((ret = WSAStartup(MAKEWORD(2, 2), &wsaData)) != 0) {
        cout << "WSAStartup调用失败" << endl;
        return -1;
    }

    //创建套接字socket

    if((ServerSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET) {
        cout << "创建套接字失败" << WSAGetLastError() << endl;
        WSACleanup();
        return -1;
    }

    //绑定套接字
    ServerAddr.sin_family = AF_INET;
    ServerAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
    ServerAddr.sin_port = htons(atoi(argv[1]));
    
    if(bind(ServerSocket, (SOCKADDR *)&ServerAddr, sizeof(ServerAddr)) == SOCKET_ERROR) {
        cout << "绑定套接字失败 " << WSAGetLastError() << endl;
        closesocket(ServerSocket);
        WSACleanup();
        return -1;
    }
    int ClientLen = sizeof(ClientAddr);
    cout << "端口:" << argv[1] << "正在接收数据...." << endl;
    while (true) {
        //接收数据
        ZeroMemory(buf, sizeof(buf));
        if ((ret = recvfrom(ServerSocket, buf, sizeof(buf), 0, (SOCKADDR *)&ClientAddr, &ClientLen)) == SOCKET_ERROR) {
            cout << "接收数据失败" << WSAGetLastError() << endl;
            closesocket(ServerSocket);
            WSACleanup();
            return -1;
        }
        else {
            //发送数据
            cout << "服务端: " << buf << endl;
            sendto(ServerSocket, buf, sizeof(buf), 0, (SOCKADDR *)&ClientAddr, ClientLen);
        }
    }

    closesocket(ServerSocket);
    WSACleanup();
    return 0;
}

客户端：

#include<WinSock2.h>
#include<iostream>
#pragma comment(lib, "ws2_32.lib")
#pragma warning(disable:4996) //忽略旧函数使用缺陷的警告

using namespace std;

int main(int argc, char * argv[]) {
    const int BUFSIZE = 1024;
    WSADATA     WSAData;
    SOCKET      ClientSocket;
    SOCKADDR_IN ClientAddr;
    char        buf[BUFSIZE];
    
    WSAStartup(MAKEWORD(2, 2), &WSAData);


    //创建套接字
    ClientSocket = socket(AF_INET,SOCK_DGRAM , IPPROTO_UDP);
    
    ClientAddr.sin_addr.s_addr = inet_addr(argv[1]);
    ClientAddr.sin_port = htons(atoi(argv[2]));
    ClientAddr.sin_family = AF_INET;
    
    int ClientAddrLen = sizeof(ClientAddr);
    //发送数据
    while (true) {
        ZeroMemory(buf, sizeof(buf));
        cout << "客户端: ";
        cin >> buf;
        sendto(ClientSocket, buf, sizeof(buf), 0, (SOCKADDR *)&ClientAddr, sizeof(ClientAddr));
        recvfrom(ClientSocket, buf, sizeof(buf), 0, (SOCKADDR *)&ClientAddr, &ClientAddrLen);

        cout << "服务端: " << buf << endl;
    }

    closesocket(ClientSocket);
    WSACleanup();
    return 0;
}

WinSock UDP 短连接