How can I check if a string has special characters in C++ effectively?

Question

I am trying to find if there is better way to check if the string has special characters. In my case, anything other than alphanumeric and a \'_\' is considered a special charac

Answer 1

Try:

std::string  x(/*Load*/);
if (x.find_first_not_of("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890_") != std::string::npos)
{
    std::cerr << "Error\n";
}

Or try boost regular expressions:

// Note: \w matches any word character `alphanumeric plus "_"`
boost::regex test("\w+", re,boost::regex::perl);
if (!boost::regex_match(x.begin(), x.end(), test)
{
    std::cerr << "Error\n";
}

// The equivalent to \w should be:
boost::regex test("[A-Za-z0-9_]+", re,boost::regex::perl);