#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>

#define SERVER_PORT 12345  // 服務(wù)器端口號(hào)
#define SERVER_IP "127.0.0.1"  // 服務(wù)器IP地址
#define BUFFER_SIZE 1024  // 緩沖區(qū)大小
 
int main() {
    int sockfd;
    struct sockaddr_in server_addr;
    char buffer[BUFFER_SIZE];
    socklen_t addr_len;
    ssize_t n;
 
    // 創(chuàng)建UDP套接字
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("創(chuàng)建套接字失敗");
        exit(EXIT_FAILURE);
    }
 
    // 配置服務(wù)器地址
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;  // 使用IPv4地址
    server_addr.sin_port = htons(SERVER_PORT);  // 設(shè)置端口號(hào)，轉(zhuǎn)換為網(wǎng)絡(luò)字節(jié)序
    inet_pton(AF_INET, SERVER_IP, &server_addr.sin_addr);  // 將IP地址從文本格式轉(zhuǎn)換為二進(jìn)制格式
 
    // 發(fā)送消息到服務(wù)器
    const char *message = "Hello, UDP Server!";
    sendto(sockfd, message, strlen(message), 0, (struct sockaddr *)&server_addr, sizeof(server_addr));
    printf("已向服務(wù)器發(fā)送消息：%s\n", message);
 
    // 接收服務(wù)器的響應(yīng)
    addr_len = sizeof(server_addr);
    n = recvfrom(sockfd, buffer, BUFFER_SIZE, 0, (struct sockaddr *)&server_addr, &addr_len);
    if (n > 0) {
        buffer[n] = '\0';  // 確保字符串以'\0'結(jié)尾
        printf("接收到服務(wù)器的響應(yīng)：%s\n", buffer);
    } else {
        printf("未接收到服務(wù)器的響應(yīng)或接收出錯(cuò)。\n");
    }
 
    // 關(guān)閉套接字
    close(sockfd);
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
 
#define PORT 12345
#define BUFFER_SIZE 1024
 
int main() {
    int sockfd;
    char buffer[BUFFER_SIZE];
    struct sockaddr_in server_addr, client_addr;
    socklen_t addr_len;
    ssize_t n;
 
    // 創(chuàng)建UDP套接字
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("創(chuàng)建套接字失敗");
        exit(EXIT_FAILURE);
    }
 
    // 配置服務(wù)器地址
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(PORT);
 
    // 綁定套接字
    if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("綁定失敗");
        close(sockfd);
        exit(EXIT_FAILURE);
    }
 
    printf("UDP服務(wù)器已啟動(dòng)，正在監(jiān)聽端口 %d...\n", PORT);
 
    // 接收客戶端的消息
    addr_len = sizeof(client_addr);
    n = recvfrom(sockfd, buffer, BUFFER_SIZE, 0, (struct sockaddr *)&client_addr, &addr_len);
    if (n > 0) {
        buffer[n] = '\0';
        printf("接收到來自客戶端的消息：%s\n", buffer);
 
        // 向客戶端發(fā)送響應(yīng)
        const char *response = "服務(wù)器已收到您的消息";
        sendto(sockfd, response, strlen(response), 0, (struct sockaddr *)&client_addr, addr_len);
    }
 
    // 關(guān)閉套接字
    close(sockfd);
    return 0;
}