windows c语言 udp

以下是一个简单的 Windows C 语言 UDP 服务器和客户端示例：

服务器端：

#include <stdio.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib") // 链接 winsock 库

int main() {
    WSADATA wsaData;
    SOCKET serverSocket, clientSocket;
    struct sockaddr_in serverAddr, clientAddr;
    int clientAddrLen = sizeof(clientAddr);
    char buffer[1024];

    // 初始化 winsock 库
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("初始化 winsock 失败！\n");
        return 1;
    }

    // 创建 UDP 套接字
    if ((serverSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET) {
        printf("创建套接字失败！\n");
        WSACleanup();
        return 1;
    }

    // 绑定地址和端口
    memset(&serverAddr, 0, sizeof(serverAddr));
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    serverAddr.sin_port = htons(8888);
    if (bind(serverSocket, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
        printf("绑定地址和端口失败！\n");
        closesocket(serverSocket);
        WSACleanup();
        return 1;
    }

    printf("服务器已启动，等待客户端连接...\n");

    // 接收数据并回复客户端
    while (1) {
        memset(buffer, 0, sizeof(buffer));
        if (recvfrom(serverSocket, buffer, sizeof(buffer), 0, (struct sockaddr*)&clientAddr, &clientAddrLen) == SOCKET_ERROR) {
            printf("接收数据失败！\n");
            break;
        }
        printf("客户端 %s:%d 发来消息：%s\n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), buffer);
        if (sendto(serverSocket, buffer, strlen(buffer), 0, (struct sockaddr*)&clientAddr, clientAddrLen) == SOCKET_ERROR) {
            printf("回复客户端失败！\n");
            break;
        }
    }

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

客户端：

#include <stdio.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib") // 链接 winsock 库

int main() {
    WSADATA wsaData;
    SOCKET clientSocket;
    struct sockaddr_in serverAddr;
    char buffer[1024];

    // 初始化 winsock 库
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("初始化 winsock 失败！\n");
        return 1;
    }

    // 创建 UDP 套接字
    if ((clientSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET) {
        printf("创建套接字失败！\n");
        WSACleanup();
        return 1;
    }

    // 设置服务器地址和端口
    memset(&serverAddr, 0, sizeof(serverAddr));
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    serverAddr.sin_port = htons(8888);

    // 发送数据并接收回复
    while (1) {
        printf("请输入消息（输入 q 退出）：\n");
        fgets(buffer, sizeof(buffer), stdin);
        if (strcmp(buffer, "q\n") == 0) {
            break;
        }
        if (sendto(clientSocket, buffer, strlen(buffer), 0, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
            printf("发送数据失败！\n");
            break;
        }
        memset(buffer, 0, sizeof(buffer));
        if (recvfrom(clientSocket, buffer, sizeof(buffer), 0, NULL, NULL) == SOCKET_ERROR) {
            printf("接收回复失败！\n");
            break;
        }
        printf("服务器回复：%s\n", buffer);
    }

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

注意：需要在 Visual Studio 中设置项目属性，将字符集设置为“使用多字节字符集”，否则中文会出现乱码。