#ifdef WIN32

 #include <windows.h>

 #include <stdio.h>

 #else

 #include <stdio.h>

 #include <sys/types.h>

 #include <sys/socket.h>

 #include <netinet/in.h>

 #include <errno.h>

 #include <unistd.h>

 #include <sys/time.h>

 #endif

 struct data6

 {

     unsigned int d4:;

     unsigned int d3:;

     unsigned int d2:;

     unsigned int d1:;

 };

 // 协议中加密部分使用的是base64方法

 char con628(char c6);

 void base64(char *dbuf,char *buf128,int len);

 void sendemail(char *email,char *body);

 int open_socket(struct sockaddr *addr);

 int main()

 {

     char email[] = "987654321@qq.com";

     char body[] = "From: \"lucy\"<123456789@qq.com>\r\n"

     "To: \"dasiy\"<987654321@qq.com>\r\n"

     "Subject: Hello\r\n\r\n"

     "Hello World, Hello Email!";

     sendemail(email, body);

     return ;

 }

 char con628(char c6)

 {

     char rtn = '\0';

     if (c6 < ) rtn = c6 + ;

     else if (c6 < ) rtn = c6 + ;

     else if (c6 < ) rtn = c6 - ;

     else if (c6 == ) rtn = ;

     else rtn = ;

     return rtn;

 }

 // base64的实现

 void base64(char *dbuf, char *buf128, int len)

 {

     struct data6 *ddd = NULL;

     int i = ;

     char buf[] = {};

     char *tmp = NULL;

     char cc = '\0';

     memset(buf, , );

     strcpy(buf, buf128);

     for(i = ; i <= len/; i++)

     {

     tmp = buf+(i-)*;

     cc = tmp[];

     tmp[] = tmp[];

     tmp[] = cc;

     ddd = (struct data6 *)tmp;

     dbuf[(i-)*+] = con628((unsigned int)ddd->d1);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d2);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d3);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d4);

     }

     if(len% == )

     {

     tmp = buf+(i-)*;

     cc = tmp[];

     tmp[] = tmp[];

     tmp[] = cc;

     ddd = (struct data6 *)tmp;

     dbuf[(i-)*+] = con628((unsigned int)ddd->d1);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d2);

     dbuf[(i-)*+] = '=';

     dbuf[(i-)*+] = '=';

     }

     if(len% == )

     {

     tmp = buf+(i-)*;

     cc = tmp[];

     tmp[] = tmp[];

     tmp[] = cc;

     ddd = (struct data6 *)tmp;

     dbuf[(i-)*+] = con628((unsigned int)ddd->d1);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d2);

     dbuf[(i-)*+] = con628((unsigned int)ddd->d3);

     dbuf[(i-)*+] = '=';

     }

     return;

 }

 // 发送邮件

 void sendemail(char *email, char *body)

 {

     int sockfd = ;

     struct sockaddr_in their_addr = {};

     char buf[] = {};

     char rbuf[] = {};

     char login[] = {};

     char pass[] = {};

     #ifdef WIN32

     WSADATA WSAData;

     WSAStartup(MAKEWORD(, ), &WSAData);

     #endif

     memset(&their_addr, , sizeof(their_addr));

     their_addr.sin_family = AF_INET;

     their_addr.sin_port = htons();

     their_addr.sin_addr.s_addr = inet_addr("112.90.141.71");//qq smtp 服务器

     // 连接邮件服务器，如果连接后没有响应，则2 秒后重新连接

     sockfd = open_socket((struct sockaddr *)&their_addr);

     memset(rbuf,,);

     while(recv(sockfd, rbuf, , ) == )

     {

         printf("reconnect...\n");

         Sleep();

         //close(sockfd);

         sockfd = open_socket((struct sockaddr *)&their_addr);

         memset(rbuf,,);

     }

     printf("%s\n", rbuf);

     // EHLO

     memset(buf, , );

     sprintf(buf, "EHLO abcdefg-PC\r\n");

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // AUTH LOGIN

     memset(buf, , );

     sprintf(buf, "AUTH LOGIN\r\n");

     send(sockfd, buf, strlen(buf), );

     printf("%s\n", buf);

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // USER

     memset(buf, , );

     sprintf(buf,"");//你的qq号

     memset(login, , );

     base64(login, buf, strlen(buf));

     sprintf(buf, "%s\r\n", login);

     send(sockfd, buf, strlen(buf), );

     printf("%s\n", buf);

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // PASSWORD

     sprintf(buf, "qqpassword");//你的qq密码

     memset(pass, , );

     base64(pass, buf, strlen(buf));

     sprintf(buf, "%s\r\n", pass);

     send(sockfd, buf, strlen(buf), );

     printf("%s\n", buf);

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // MAIL FROM

     memset(buf, , );

     sprintf(buf, "MAIL FROM: <123456789@qq.com>\r\n");

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // RCPT TO 第一个收件人

     sprintf(buf, "RCPT TO:<%s>\r\n", email);

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // DATA 准备开始发送邮件内容

     sprintf(buf, "DATA\r\n");

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // 发送邮件内容，\r\n.\r\n内容结束标记

     sprintf(buf, "%s\r\n.\r\n", body);

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

     // QUIT

     sprintf(buf, "QUIT\r\n");

     send(sockfd, buf, strlen(buf), );

     memset(rbuf, , );

     recv(sockfd, rbuf, , );

     printf("%s\n", rbuf);

 // VC2005 需要使用

     closesocket(sockfd);

 //    close(sockfd);

     #ifdef WIN32

     WSACleanup();

     #endif

     return;

 }

     // 打开TCP Socket连接

 int open_socket(struct sockaddr *addr)

 {

         int sockfd = ;

         sockfd=socket(PF_INET, SOCK_STREAM, );

         if(sockfd < )

         {

             fprintf(stderr, "Open sockfd(TCP) error!\n");

             exit(-);

         }

         if(connect(sockfd, addr, sizeof(struct sockaddr)) < )

         {

             fprintf(stderr, "Connect sockfd(TCP) error!\n");

             exit(-);

         }

         return sockfd;

 }