C ++中的电子邮件验证 [英] Email validation in C++

问题描述

好的，我正在尝试制作一个程序，允许用户输入电子邮件。如果满足两个规定，他们的电子邮件将被视为有效：A.那里必须有一个 @符号，B。必须在 @之后有一个句点。我大部分时间都记下来了代码，但是在验证带有 @符号的句点的电子邮件时遇到了一些困难。如果它们在 @符号前有句点，则认为它们是有效的，但实际上不应该。例如，输入 text.example@randomcom 被认为是有效的。

Okay so I'm trying to make a program which allows user to input their email. Their email will be considered valid if two stipulations are met: A. there must be an "@" sign somewhere in there and B. there must be a period after the "@". I got the code down for the most part, but I am having some difficulty when it comes to validating emails that have a period before the "@" sign. If they have the period before the "@" sign they are considered valid, but they shouldn't be. For example, entering text.example@randomcom is considered valid.

有人可以帮我弄清楚我做了什么吗？错误？

Can anyone help me figure out what I did wrong? Thank you in advance!

#include <iostream>
#include <cctype>
#include <cstring>
using namespace std;

int main()
{
    int x = 25; //random size enough to hold contents of array plus one for               null terminator
    char input[x]; //array to hold input
    int sizeOf; //holds length of input array
    char* ptr = nullptr; //pointer
    char* ptr2 = nullptr; //pointer

    cout << "Enter your email address\n";
    cin.getline(input,x);
    sizeOf = strlen(input);

    for(int i = 0; i < sizeOf; i++)
    {
        ptr= strstr(input, "@"); //searches input array for "@" string
        if(ptr != nullptr) 
        {
            break;
        }
    }

    for(int i = 0; i < sizeOf; i++)
    {
        ptr2 = strstr(input, "."); //searches input array for "." string
        if(ptr2 != nullptr && &ptr2 > &ptr)
        {
            break;
        }
    }

    if(ptr != nullptr) //validates input of "@" sign
    {
        if(ptr2 != 0 && &ptr2 < &ptr) 
            {
                cout << "Email accepted.\n";
            }

        else
            {
                cout << "Missing . symbol after @\n";
            }
    }

    else
    {
        cout << "Missing @ symbol\n";
    }



return 0;
}

推荐答案

为什么不使用正则表达式？

Why not use regex?

#include <iostream>
#include <string>
#include <regex>

bool is_email_valid(const std::string& email)
{
   // define a regular expression
   const std::regex pattern
      ("(\\w+)(\\.|_)?(\\w*)@(\\w+)(\\.(\\w+))+");

   // try to match the string with the regular expression
   return std::regex_match(email, pattern);
}

int main()
{
    std::string email1 = "text.example@randomcom";

    std::cout << email1 << " : " << (is_email_valid(email1) ?
      "valid" : "invalid") << std::endl;
}

http://en.cppreference.com/w/cpp/regex

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