C++发送邮件实现

首先，别忘了要设置发送邮箱的smtp，例如，假设你需要用网易邮箱，你需要去你的163邮箱设置开启smtp（有的邮箱还需要设置授权码）。接着就可以用以下代码发送邮件了:

// SendMail.h#ifndef _SEND_MAIL_H_#define _SEND_MAIL_H_#include <windows.h>#include <stdio.h>#include <WinSock.h>#include <iostream>using namespace std;// 协议中加密部分使用的是base64方法char ConvertToBase64(char c6);void EncodeBase64(char *dbuf, char *buf128, int len);void SendMail(char *email, const char *body);int  OpenSocket(struct sockaddr *addr);#endif

// SendMail.cpp#include "SendMail.h"#pragma  comment(lib, "ws2_32.lib")struct Base64Date6{    unsigned int d4 : 6;    unsigned int d3 : 6;    unsigned int d2 : 6;    unsigned int d1 : 6;};char ConvertToBase64(char uc){    if (uc < 26)    {        return 'A' + uc;    }    if (uc < 52)    {        return 'a' + (uc - 26);    }    if (uc < 62)    {        return '0' + (uc - 52);    }    if (uc == 62)    {        return '+';    }    return '/';}// base64的实现void EncodeBase64(char *dbuf, char *buf128, int len){    struct Base64Date6 *ddd = NULL;    int           i = 0;    char          buf[256] = { 0 };    char          *tmp = NULL;    char          cc = '\0';    memset(buf, 0, 256);    strcpy_s(buf, 256, buf128);    for (i = 1; i <= len / 3; i++)    {        tmp = buf + (i - 1) * 3;        cc = tmp[2];        tmp[2] = tmp[0];        tmp[0] = cc;        ddd = (struct Base64Date6 *)tmp;        dbuf[(i - 1) * 4 + 0] = ConvertToBase64((unsigned int)ddd->d1);        dbuf[(i - 1) * 4 + 1] = ConvertToBase64((unsigned int)ddd->d2);        dbuf[(i - 1) * 4 + 2] = ConvertToBase64((unsigned int)ddd->d3);        dbuf[(i - 1) * 4 + 3] = ConvertToBase64((unsigned int)ddd->d4);    }    if (len % 3 == 1)    {        tmp = buf + (i - 1) * 3;        cc = tmp[2];        tmp[2] = tmp[0];        tmp[0] = cc;        ddd = (struct Base64Date6 *)tmp;        dbuf[(i - 1) * 4 + 0] = ConvertToBase64((unsigned int)ddd->d1);        dbuf[(i - 1) * 4 + 1] = ConvertToBase64((unsigned int)ddd->d2);        dbuf[(i - 1) * 4 + 2] = '=';        dbuf[(i - 1) * 4 + 3] = '=';    }    if (len % 3 == 2)    {        tmp = buf + (i - 1) * 3;        cc = tmp[2];        tmp[2] = tmp[0];        tmp[0] = cc;        ddd = (struct Base64Date6 *)tmp;        dbuf[(i - 1) * 4 + 0] = ConvertToBase64((unsigned int)ddd->d1);        dbuf[(i - 1) * 4 + 1] = ConvertToBase64((unsigned int)ddd->d2);        dbuf[(i - 1) * 4 + 2] = ConvertToBase64((unsigned int)ddd->d3);        dbuf[(i - 1) * 4 + 3] = '=';    }    return;}// 发送邮件void SendMail(char *email, const char *body){    int     sockfd = { 0 };    char    buf[1500] = { 0 };    char    rbuf[1500] = { 0 };    char    login[128] = { 0 };    char    pass[128] = { 0 };    WSADATA WSAData;    struct sockaddr_in their_addr = { 0 };    WSAStartup(MAKEWORD(2, 2), &WSAData);    memset(&their_addr, 0, sizeof(their_addr));    their_addr.sin_family = AF_INET;    their_addr.sin_port = htons(25);    // 一般是25端口不需要改    hostent* hptr = gethostbyname("smtp.126.com");          // 端口和服务器    memcpy(&their_addr.sin_addr.S_un.S_addr, hptr->h_addr_list[0], hptr->h_length);    printf("IP of smpt.163.com is : %d:%d:%d:%d\n",        their_addr.sin_addr.S_un.S_un_b.s_b1,        their_addr.sin_addr.S_un.S_un_b.s_b2,        their_addr.sin_addr.S_un.S_un_b.s_b3,        their_addr.sin_addr.S_un.S_un_b.s_b4);    // 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 = OpenSocket((struct sockaddr *)&their_addr);    memset(rbuf, 0, 1500);    while (recv(sockfd, rbuf, 1500, 0) == 0)    {        cout << "reconnect..." << endl;        Sleep(2);        sockfd = OpenSocket((struct sockaddr *)&their_addr);        memset(rbuf, 0, 1500);    }    cout << rbuf << endl;    // EHLO    memset(buf, 0, 1500);    sprintf_s(buf, 1500, "EHLO HYL-PC\r\n");    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "EHLO REceive: " << rbuf << endl;    // AUTH LOGIN    memset(buf, 0, 1500);    sprintf_s(buf, 1500, "AUTH LOGIN\r\n");    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Auth Login Receive: " << rbuf << endl;    // USER    memset(buf, 0, 1500);    sprintf_s(buf, 1500, "[e-mail]");//你的邮箱账号    memset(login, 0, 128);    EncodeBase64(login, buf, strlen(buf));    sprintf_s(buf, 1500, "%s\r\n", login);    send(sockfd, buf, strlen(buf), 0);    cout << "Base64 UserName: " << buf << endl;    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "User Login Receive: " << rbuf << endl;    // PASSWORD    sprintf_s(buf, 1500, "********");//你的邮箱密码    memset(pass, 0, 128);    EncodeBase64(pass, buf, strlen(buf));    sprintf_s(buf, 1500, "%s\r\n", pass);    send(sockfd, buf, strlen(buf), 0);    cout << "Base64 Password: " << buf << endl;    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Send Password Receive: " << rbuf << endl;    // MAIL FROM    memset(buf, 0, 1500);    sprintf_s(buf, 1500, "MAIL FROM: <[e-mail]>\r\n");  //此处要和发邮件的邮箱保持一致    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "set Mail From Receive: " << rbuf << endl;    // RCPT TO 第一个收件人    sprintf_s(buf, 1500, "RCPT TO:<%s>\r\n", email);    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Tell Sendto Receive: " << rbuf << endl;    // DATA 准备开始发送邮件内容    sprintf_s(buf, 1500, "DATA\r\n");    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Send Mail Prepare Receive: " << rbuf << endl;    // 发送邮件内容，\r\n.\r\n内容结束标记    sprintf_s(buf, 1500, "%s\r\n.\r\n", body);    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Send Mail Receive: " << rbuf << endl;    // QUIT    sprintf_s(buf, 1500, "QUIT\r\n");    send(sockfd, buf, strlen(buf), 0);    memset(rbuf, 0, 1500);    recv(sockfd, rbuf, 1500, 0);    cout << "Quit Receive: " << rbuf << endl;    //清理工作    closesocket(sockfd);    WSACleanup();    return;}// 打开TCP Socket连接int OpenSocket(struct sockaddr *addr){    int sockfd = 0;    sockfd = socket(PF_INET, SOCK_STREAM, 0);    if (sockfd < 0)    {        cout << "Open sockfd(TCP) error!" << endl;        exit(-1);    }    if (connect(sockfd, addr, sizeof(struct sockaddr)) < 0)    {        cout << "Connect sockfd(TCP) error!" << endl;        exit(-1);    }    return sockfd;}

测试例程：

// SendMailTest.cpp#include "SendMail.h"int main(){    int num = 100;    string EmailContents = "From: \"lucy\"<[e-mail]>\r\n"                            + string("To: \"dasiy\"<[e-mail]>\r\n")                           + "Subject: Hello\r\n\r\n"                            + "test sending variable" + to_string(num) + "\n";    char EmailTo[] = "[e-mail]";    //此处是送达的邮箱, 需和EmailContents里的保持一致    SendMail(EmailTo, EmailContents.c_str());    return 0;}