求源码（TCP或者UDP）C语言

Question

实现一个答题抱答系统，1)服务端出题，题目来自题库文件2)多个客户端可同时与服务端连接，抢答题目，题目有1人答对或答题超时，服务端换下一题3)答题结束，服务端向客户端公布成绩和排名

Answer 1

采用Linux的socket机制通信就行了, 以下是本人稍稍封装的头文件sock.h, 若是能解决你的问题, 再加上源文件

#ifndef __SOCK_H
#define __SOCK_H

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
#include <stddef.h>
#include <string.h>

/* ===== API for simple INET/UNIX socket ===== */


/*
   Create a server
   If port is valid, create an INET server.
   Otherwise, create an UNIX server.
   Return serverfd for OK, negetive value for ERR
   Example:
       [INET Server]
       int serverfd;
       if ((serverfd = sock_server(2333, NULL, 5)) < 0)
       {
           prinf("Error: fail to create server\n");
       }
       [UNIX Server]
       int serverfd;
       if ((serverfd = sock_server(-1, "test.sock", 5)) < 0)
       {
           prinf("Error: fail to create server\n");
       }
*/
int sock_server(int port, const char *sockfile, int max_connection);

/*
   Accept a client and create a session
   Return sessionfd for OK, negetive value for ERR
   Example:
       int sessionfd;
       if ((sessionfd = sock_accept(serverfd)) < 0)
       {
           prinf("Error: fail to accept client\n");
       }
*/
int sock_accept(int serverfd);

/*
   Create a client connected to a server
   If host and port are valid, create an INET client.
   Otherwise, create an UNIX client.
   Return clientfd for OK, negetive value for ERR
   Example:
       [INET Client]
       int clientfd;
       if ((clientfd = sock_client("127.0.0.1", 2333, NULL)) < 0)
       {
           printf("Error: fail to create client\n");
       }
       [UNIX Client]
       int clientfd;
       if ((clientfd = sock_client(NULL, -1, "test.sock")) < 0)
       {
           prinf("Error: fail to create client\n");
       }
*/
int sock_client(const char *host, int port, const char *sockfile);

/*
   Close a server/client/session
   Example:
       close(clientfd);
       close(sessionfd);
       close(serverfd);
*/
void sock_close(int fd);


/*
   Send message
   Return message length sent for OK, negetive value for ERR
   Example:
       if ((sock_send(clientfd, msg, msg_len) < 0)
       {
           printf("Error: fail to send message\n");
       }
*/
ssize_t sock_send(int sockfd, const void *buf, size_t len);

/*
   Receive message
   Return message length received for OK, negetive value for ERR
   Example:
       if ((msg_len = sock_recv(sessionfd, buf, MAX_LEN) < 0)
       {
           printf("Error: fail to receive message\n");
       }
*/
ssize_t sock_recv(int sockfd, void *buf, size_t len);

/*
   Sock Example:

   [Sever]
    int serverfd;
    int sessionfd;
    char buf[512];
    int len;
    if ((serverfd = sock_server(-1, "test.sock", 5)) < 0)
    {
        exit(-1);
    }
    if ((sessionfd = sock_accept(serverfd)) < 0)
    {
        exit(-2);
    }
    if ((len = sock_recv(sessionfd, buf, 512)) > 0)
    {
        buf[len] = 0;
        printf("Recv: %s\n", buf);
    }
    sock_close(sessionfd);
    sock_close(serverfd);   

   [Client]
    int clientfd;
    char buf[512];
    int len;
    if ((clientfd = sock_client(NULL, -1, "test.sock")) < 0)
    {
        exit(-1);
    }
    sprintf(buf, "Hello world");
    len = strlen(buf);
    if ((len = sock_send(clientfd, buf, len)) > 0)
    {
        printf("Send: %s\n", buf);
    }
    sock_close(clientfd);
*/

#endif