基于UDP传输的C语言聊天小程序

下面是一个简单的UDP聊天程序的示例代码，实现了客户端和服务器端的基本功能。

服务器端 (server.c):

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
 
#define BUF_SIZE 1024
#define SERVER_PORT 8888
 
int main() {
    struct sockaddr_in server_addr, client_addr;
    socklen_t addr_len;
    int sock_fd;
    char buf[BUF_SIZE];
    int i, res;
 
    // 创建socket
    sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
 
    // 定义服务器地址
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(SERVER_PORT);
 
    // 绑定socket到地址
    bind(sock_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
 
    printf("Server is running on port %d, waiting for messages...\n", SERVER_PORT);
 
    while (1) {
        addr_len = sizeof(client_addr);
        // 接收数据
        res = recvfrom(sock_fd, buf, BUF_SIZE, 0, (struct sockaddr *)&client_addr, &addr_len);
        if (res == -1) {
            perror("recvfrom error");
            continue;
        }
        buf[res] = '\0';
        printf("Received message: %s\n", buf);
 
        // 发送数据回客户端
        strcat(buf, " (from server)");
        res = sendto(sock_fd, buf, strlen(buf), 0, (struct sockaddr *)&client_addr, addr_len);
        if (res == -1) {
            perror("sendto error");
        }
    }
 
    close(sock_fd);
    return 0;
}

客户端 (client.c):

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
 
#define BUF_SIZE 1024
#define SERVER_PORT 8888
#define SERVER_IP "127.0.0.1"
 
int main() {
    struct sockaddr_in server_addr;
    int sock_fd;
    char buf[BUF_SIZE];
    int res;
 
    // 创建socket
    sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
 
    // 定义服务器地址
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);
    server_addr.sin_port = htons(SERVER_PORT);
 
    printf("Chat client is running, enter messages and hit enter to send.\n");
 
    while (fgets(buf, BUF_SIZE, stdin) != NULL) {
        // 发送数据到服务器
        res = sendto(sock_fd, buf, strlen(buf), 0, (struct sockaddr *)&server_addr, sizeof(server_addr));
        if (res == -1) {
            perror("sendto error");
            continue;
        }
 
        // 接收来