Untitled

void check_email()
{
    bool flag = true;
    char tav = NULL;
    cout<<"Enter email"<<endl;
    cin>>tav;
    //getchar();
    
    while (tav != ' ')
    {
      while(tav != '@')
      {
        if (flag == true)
        {
            if ((tav >= 'a') == false && (tav <= 'z') == false && (tav >= 'A') == false && (tav <= 'Z') == false && (tav >= '0') == false && (tav <= '9')== false && (tav == '@') == false && (tav == '.') == false && (tav == '_') == false)
            {
                flag = false;
                cout<<"Try again : your email address is not correct"<<endl;
                cin>>tav;
                getchar();
            }
        }
        else if (tav == true && tav == '@')
        {
            if ((tav >= 'a') == false && (tav <= 'z') == false && (tav >= 'A') == false && (tav <= 'Z') == false && (tav>= '0') == false && (tav <='9') == false && (tav == '.') == false)
            {
                
                    flag = false;
                    cout<<"Try again : your email address is not correct"<<endl;
                    cin>>tav;
                    getchar();
                
            }
            else
            {
                flag = true;
            }
        }
      }
        
        
    }
    cout<<"Your email address is correct"<<endl;
   
}