STL exception sample

STL-exception-sample-example.cpp

// STL-exception-sample-example.cpp

// STL exception sample

// How to build: 
// 1) gcc 
//     g++ -lstdc++ main.cpp
// 2) visual studio (visual c++)
//     just do it!
// 

#include <iostream>
#include <sstream>
#include <memory>
#include <stdexcept> 

using namespace std;

class StreamingException : public std::runtime_error
{
public:
	StreamingException() :
	std::runtime_error(""),
		ss_(std::auto_ptr<std::stringstream>
		   (new std::stringstream()))
	{
	}

	~StreamingException() throw()
	{
	}

	template <typename T>
	StreamingException & operator << (const T & t)
	{
		(*ss_) << t;
		return *this;
	}

	virtual const char * what() const throw()
	{
		s_ = ss_->str();
		return s_.c_str();
	}

private:
	mutable std::auto_ptr<std::stringstream> ss_;
	mutable std::string s_;
};

int main (int argc, char * const argv[]) 
{  
  try
  {
    if (5 != 3)
      throw StreamingException() << 5 << " is not equal to " << 3;
  }
  catch (const StreamingException & e)
  {
    cout << " StreamingException : "; 
    cout << e.what() << endl;
  }

  return 0;
}