xhtml special characters between different browsers - c++

Question

i am working on a cgi program , i am receiving an email address like this : someone#site.com and storing it in a file.
but some thing strange happens. when i use IE the '#' char , won't change and it is same in the file , but when i use chrome , '#' char ,changes to %40 and the only way to retrieve the '#' is to find %40 and replace it with '#'.am i coding wrong or chrome has problem?
to understand better :
IE: someone#site.com
Chrome:someone%40site.com
and when i send information back to the browser , %40 doesn't change to #

Answer 1

It's IE that's doing it wrong in actual fact - You need to change the %xx code back to a character. In the case of %40 this would be ASCII no. 0x40 == 64 == '#'. You can't rely on it being ASCII, however, as unicode characters (such as accented letters) will also be similarly encoded.
Most languages like PHP and Python have a helper function to encode and decode these (PHP's is called url_encode() and url_decode()) - I've not used CGI on C++ for a long while, so not sure if there's a helper readily available or if you'll have to code your own - either way you should be prepared to decode url-encoded strings as all browsers will do this for some characters if not all (eg. %20 instead of a space is very common).
Hope this helps!

Answer 2

the answer above is correct , just in make the topic richer i think this peace of code can be the function you use :
int main()
{
int number;
string dataString="hi %40 c++ programmer %40 !";
string transform;
istringstream input;
string::size_type location = dataString.find("%");
while (location <string::npos)
{
transform = dataString.substr(location+1, 2);
input.str(transform);
input >> hex >> number;
dataString.replace(location,3,1,static_cast<char>(number));
location = dataString.find("%", location+1);
}
cout << dataString << endl;
}