Convert PHP chr()/strval() function to C++

Question

I'm trying to convert a library of character manipulation from PHP to C++.

1) I've used static_cast<char>() to replace all single chr() functions (applied only to a single char, ie: PHP: $out = chr(50); => C++: std::string s = static_cast<char>(50)).

Is this correct?

2) Given the following PHP code :

$crypt = chr(strval(substr("5522446633",0,2)));

In this snippet, we extract 2 char from the string "5522446633", and "get their string values" (PHP manual) from the function strval().

I know how to get the (integer) value from one char in C++, but how can I do with two chars?

How can I translate this snippet to C++?

Answer 1

The following code is equivalent to your php code:

#include <iostream>
#include <string>

std::string convert(const std::string& value)
{
  size_t pos;
  try
  {
      std::string sub = value.substr(0,2);
      int chr = std::stoi(sub, &pos);
      if (pos != sub.size())
      {
          return "";
      }
      return std::string(1, static_cast<char>(chr & 255));
  }
  catch ( std::exception& )
  {
      return "";
  }
}

int main()
{
  std::cout << convert("5522446633") << "\n";
}