1 /* UDPServer.cpp */ 2  3 #include <stdlib.h> 4 #include <stdio.h> 5 #include <winsock2.h> 6 #include <string.h> 7 #include "conio.h" 8 #include <time.h> 9 10 #define    BUFLEN        2000                  // 缓冲区大小11 #define WSVERS        MAKEWORD(2, 2)        // 指明版本2.2 12 #pragma comment(lib,"ws2_32.lib")         // 加载winsock 2.2 Llibrary13 14 /*------------------------------------------------------------------------15  * main - TCP client for DAYTIME service16  *------------------------------------------------------------------------17  */18 void19 main(int argc, char *argv[])20 {21     char   *host = "127.0.0.1";        /* server IP Address to connect */22 23     char   *service = "5050";          /* server port to connect       */24     struct sockaddr_in sin;            /* an Internet endpoint address    */25     struct sockaddr_in from;        /* sender address               */26     int    fromsize = sizeof(from);27     char   buf[BUFLEN+1];           /* buffer for one line of text    */28     char   buf1[BUFLEN+1];  29     SOCKET    sock;                      /* socket descriptor            */30     int    cc;                            /* recv character count            */31 32     char    *pts;    33     time_t    now;34 35     WSADATA wsadata;36     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。    */        37     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_SOCKET38     memset(&sin, 0, sizeof(sin));39     sin.sin_family = AF_INET;40     sin.sin_addr.s_addr = INADDR_ANY;                     // 绑定(监听)所有的接口。41     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。 42     bind(sock, (struct sockaddr *)&sin, sizeof(sin));     // 绑定本地端口号（和本地IP地址)43 44     (void) time(&now);                                      // 取得系统时间45        pts = ctime(&now);                                      // 把时间转换为字符串46        printf("           \t     UDP(Server) Echo增强程序\n\n"); 47      while(!_kbhit()){                                    //检测是否有按键48 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。49         sprintf(buf1," \t\t 时间：  %s \t\t Client【IP: %s  端口号： %d  】\n  \t\t  数据：   %s",pts,inet_ntoa(from.sin_addr),from.sin_port,buf);50         if (cc == SOCKET_ERROR){51             printf("recvfrom() failed; %d\n", WSAGetLastError());52             break;53         }54         else if (cc == 0)55             break;56         else{57             buf[cc] = ‘\0‘;58             printf("您收到的数据为：\n   %s\n", buf1);59             printf("将自动把此数据返回给 Client  \n");60             goto flag2;61         }62 63     }64 65 flag2:    cc = sendto(sock, buf1, 1000, 0,(SOCKADDR *)&from, sizeof(from));66    if (cc == SOCKET_ERROR){67         printf("发送失败，错误号：%d\n", WSAGetLastError());68           }69     else{70         printf("发送成功\n");71         goto flag1;72          }73 74 //    cc = recvfrom(sock, buf, BUFLEN, 0, (SOCKADDR *)&from, &fromsize);75 76     closesocket(sock);77     GlobalFree(buf);78     WSACleanup();                     /* 卸载某版本的DLL */79 }

 1 /* UDPClient.cpp */ 2  3 #include <stdlib.h> 4 #include <stdio.h> 5 #include <winsock2.h> 6 #include <string.h> 7 #include <time.h> 8  9 #define    BUFLEN        2000                  // 缓冲区大小10 #define WSVERS        MAKEWORD(2, 2)        // 指明版本2.2 11 #pragma comment(lib,"ws2_32.lib")         // 加载winsock 2.2 Llibrary12 13 void14 main(int argc, char *argv[])15 {16     char    *host = "127.0.0.1";        /* server IP to connect         */17 18     char    *service = "5050";          /* server port to connect       */19     struct sockaddr_in toAddr;            /* an Internet endpoint address    */20     char    buf[BUFLEN+1];                   /* buffer for one line of text    */21     SOCKET    sock;                          /* socket descriptor            */22     int    cc;                                /* recv character count            */23     char    *pts;                    /* pointer to time string            */24     time_t    now;                    /* current time                        */25 26     int    toAddrsize = sizeof(toAddr);27 28     WSADATA wsadata;29     WSAStartup(WSVERS, &wsadata);       /* 启动某版本Socket的DLL        */    30 31     sock = socket(PF_INET, SOCK_DGRAM,IPPROTO_UDP);32 33     memset(&toAddr, 0, sizeof(toAddr));34     toAddr.sin_family = AF_INET;35     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--short36     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37 38 39 //    memset(buf,‘ ‘,1000);  //fill 1000 bytes with ‘e‘40     buf[1000] = ‘\0‘;41     (void) time(&now);                                      // 取得系统时间42     pts = ctime(&now);                                      // 把时间转换为字符串43 //    memcpy(buf,pts,strlen(pts));44     sprintf(buf,"%s ",pts);45     printf("                        UDP(Client) Echo增强程序\n\n"); 46      printf("  时间 ：%s",buf);47 48 49 50     cc = sendto(sock, buf, 1000, 0,(SOCKADDR *)&toAddr, sizeof(toAddr));51  flag2:   if (cc == SOCKET_ERROR){52         printf("发送失败，错误号：%d\n", WSAGetLastError());53      }54     else{55         printf("       发送成功 \n");56          cc = recvfrom(sock, buf, BUFLEN, 0, (SOCKADDR *)&toAddr, & toAddrsize);57          printf(" 您接收到的数据为:\n %s \n",buf);58         printf("键入 # 继续发送，键入 @ 停止发送\n");59         scanf("%s",pts);60         if(pts[0]==‘#‘)61         {62             printf("    请输入要发送的数据 ：\n");63             goto flag1;64         }65         if(pts[0]==‘@‘)66             goto end;67 68 69     }70 71 flag1:72     scanf("%s",pts);73     sprintf(buf,"%s ",pts);74     cc = sendto(sock, buf, 1000, 0,(SOCKADDR *)&toAddr, sizeof(toAddr));75 76     goto flag2;77 78 79 80     getchar();81 82     closesocket(sock);83 84 end:    GlobalFree(buf);85     WSACleanup();                     /* 卸载某版本的DLL */  86 87     getchar();88 89 }