【Echo】实验 -- 实现 C/C++下UDP, 服务器/客户端 通讯

本次实验利用UDP协议, 语言环境为 C/C++

利用套接字Socket编程，实现Server/CLient 之间简单的通讯。

结果应为类似所示：

下面贴上代码（参考参考...)

Server 部分：

/* UDPServer.cpp */

#include <stdlib.h>
#include <stdio.h>
#include <winsock2.h>
#include <string.h>
#include "conio.h"
#include <time.h>

#define    BUFLEN        2000                  // 缓冲区大小
#define WSVERS        MAKEWORD(2, 2)        // 指明版本2.2 
#pragma comment(lib,"ws2_32.lib")         // 加载winsock 2.2 Llibrary

/*------------------------------------------------------------------------
 * main - TCP client for DAYTIME service
 *------------------------------------------------------------------------
 */
void
main(int argc, char *argv[])
{
    char   *host = "127.0.0.1";        /* server IP Address to connect */

    char   *service = "5050";          /* server port to connect       */
    struct sockaddr_in sin;            /* an Internet endpoint address    */
    struct sockaddr_in from;        /* sender address               */
    int    fromsize = sizeof(from);
    char   buf[BUFLEN+1];           /* buffer for one line of text    */
    char   buf1[BUFLEN+1];  
    SOCKET    sock;                      /* socket descriptor            */
    int    cc;                            /* recv character count            */

    char    *pts;    
    time_t    now;

    WSADATA wsadata;
    WSAStartup(WSVERS, &wsadata);   /* 加载winsock library，WSVERS为请求版本,wsadata返回系统实际支持的最高版本。    */        
    sock = socket(PF_INET, SOCK_DGRAM,IPPROTO_UDP); // 创建UDP套接字, 参数：因特网协议簇(family)，数据报套接字，UDP协议号， 返回：要监听套接字的描述符或INVALID_SOCKET
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = INADDR_ANY;                     // 绑定(监听)所有的接口。
    sin.sin_port = htons((u_short)atoi(service));         // 绑定指定接口。atoi--把ascii转化为int，htons -- 主机序(host)转化为网络序(network), 为short类型。 
    bind(sock, (struct sockaddr *)&sin, sizeof(sin));     // 绑定本地端口号（和本地IP地址)

    (void) time(&now);                                      // 取得系统时间
       pts = ctime(&now);                                      // 把时间转换为字符串
       printf("           	     UDP(Server) Echo增强程序

"); 
     while(!_kbhit()){                                    //检测是否有按键
flag1:        cc = recvfrom(sock, buf, BUFLEN, 0, (SOCKADDR *)&from, &fromsize);  //接收客户数据。返回结果：cc为接收的字符数，from中将包含客户IP地址和端口号。
        sprintf(buf1," 		 时间：  %s 		 Client【IP: %s  端口号： %d  】
  		  数据：   %s",pts,inet_ntoa(from.sin_addr),from.sin_port,buf);
        if (cc == SOCKET_ERROR){
            printf("recvfrom() failed; %d
", WSAGetLastError());
            break;
        }
        else if (cc == 0)
            break;
        else{
            buf[cc] = '';
            printf("您收到的数据为：
   %s
", buf1);
            printf("将自动把此数据返回给 Client  
");
            goto flag2;
        }

    }

flag2:    cc = sendto(sock, buf1, 1000, 0,(SOCKADDR *)&from, sizeof(from));
   if (cc == SOCKET_ERROR){
        printf("发送失败，错误号：%d
", WSAGetLastError());
          }
    else{
        printf("发送成功
");
        goto flag1;
         }

//    cc = recvfrom(sock, buf, BUFLEN, 0, (SOCKADDR *)&from, &fromsize);

    closesocket(sock);
    GlobalFree(buf);
    WSACleanup();                     /* 卸载某版本的DLL */
}

Client 部分：

/* UDPClient.cpp */

#include <stdlib.h>
#include <stdio.h>
#include <winsock2.h>
#include <string.h>
#include <time.h>

#define    BUFLEN        2000                  // 缓冲区大小
#define WSVERS        MAKEWORD(2, 2)        // 指明版本2.2 
#pragma comment(lib,"ws2_32.lib")         // 加载winsock 2.2 Llibrary

void
main(int argc, char *argv[])
{
    char    *host = "127.0.0.1";        /* server IP to connect         */

    char    *service = "5050";          /* server port to connect       */
    struct sockaddr_in toAddr;            /* an Internet endpoint address    */
    char    buf[BUFLEN+1];                   /* buffer for one line of text    */
    SOCKET    sock;                          /* socket descriptor            */
    int    cc;                                /* recv character count            */
    char    *pts;                    /* pointer to time string            */
    time_t    now;                    /* current time                        */

    int    toAddrsize = sizeof(toAddr);

    WSADATA wsadata;
    WSAStartup(WSVERS, &wsadata);       /* 启动某版本Socket的DLL        */    

    sock = socket(PF_INET, SOCK_DGRAM,IPPROTO_UDP);

    memset(&toAddr, 0, sizeof(toAddr));
    toAddr.sin_family = AF_INET;
    toAddr.sin_port = htons((u_short)atoi(service));    //atoi：把ascii转化为int. htons：主机序(host)转化为网络序(network), s--short
    toAddr.sin_addr.s_addr = inet_addr(host);           //如果host为域名，需要先用函数gethostbyname把域名转化为IP地址


//    memset(buf,' ',1000);  //fill 1000 bytes with 'e'
    buf[1000] = '';
    (void) time(&now);                                      // 取得系统时间
    pts = ctime(&now);                                      // 把时间转换为字符串
//    memcpy(buf,pts,strlen(pts));
    sprintf(buf,"%s ",pts);
    printf("                        UDP(Client) Echo增强程序

"); 
     printf("  时间 ：%s",buf);



    cc = sendto(sock, buf, 1000, 0,(SOCKADDR *)&toAddr, sizeof(toAddr));
 flag2:   if (cc == SOCKET_ERROR){
        printf("发送失败，错误号：%d
", WSAGetLastError());
     }
    else{
        printf("       发送成功 
");
         cc = recvfrom(sock, buf, BUFLEN, 0, (SOCKADDR *)&toAddr, & toAddrsize);
         printf(" 您接收到的数据为:
 %s 
",buf);
        printf("键入 # 继续发送，键入 @ 停止发送
");
        scanf("%s",pts);
        if(pts[0]=='#')
        {
            printf("    请输入要发送的数据 ：
");
            goto flag1;
        }
        if(pts[0]=='@')
            goto end;


    }

flag1:
    scanf("%s",pts);
    sprintf(buf,"%s ",pts);
    cc = sendto(sock, buf, 1000, 0,(SOCKADDR *)&toAddr, sizeof(toAddr));

    goto flag2;



    getchar();

    closesocket(sock);

end:    GlobalFree(buf);
    WSACleanup();                     /* 卸载某版本的DLL */  

    getchar();

}