Question

Write a method that will have a C++ string passed to it. The string will be an email address and the method will return a bool to indicate that the email address is valid.

Email Validation Rules: ( These rules are not official.)

1) No whitespace allowed

2) 1 and only 1 @ symbol

3) 1 and only 1 period allowed after the @ symbol. Periods can exist before the @ sign.

4) 3 and only 3 characters after the period is required.

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Program will prompt for an email address and report if it is valid or not according to the rules posted above. The program will loop and prompt me to continue.

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Answer 1

validate_email.cpp

#include<iostream>
using namespace std;

bool validate(string email)
{
   int i;
   for(i=0; i<email.length();i++)
   {
       // If white space found return false
       if(email[i]==' ')
       {
           return false;
       }
       // If @ found the break the loop
       if(email[i]=='@')
       {
           i++;
           break;
       }
   }
   for(; i<email.length();i++)
   {
       // If another @ or a white space found the return false
       if(email[i]=='@' || email[i]==' ')
       {
           return false;
       }
       // If period found then break the loop
       if(email[i]=='.')
       {
           i++;
           break;
       }
   }
   // If number of characters after period is not 3 then return false
   if(email.length()-i!=3)
   {
       return false;
   }
   for(; i<email.length(); i++)
   {
       // If another @ or period or a white space found then return false
       if(email[i]=='@' || email[i]=='.' || email[i]==' ')
       {
           return false;
       }
   }
   // Execution comes here if email address is valid
   return true;
}

int main()
{
   string email;
   cout<<"Enter email address: ";
   // User input
   getline(cin,email);
   // Function calling and output printing
   validate(email)==1?cout<<"Valid":cout<<"Invalid";
   return 0;
}

output screenshot: