c++ stl bind

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <numeric>
#include <functional>

using namespace std;
using namespace std::tr1::placeholders;

string Encoder(char c)	
{
		switch (c)
		{
			case '<': return "<";
			case '>': return ">";
			case '&': return "&";
			case '\'': return "'";
			case '"': return """;
			default: return string(1, c);
		}
}

int main()
{
	string s("<1>");
	string s0("&.&");
	char c = 'c';
	cout<< multiplies<int>()(3,4)<<endl;
	//cout << plus<string>(s,c) <<endl;
	string s2 = std::accumulate(s.begin(), s.end(), string(), bind(plus<string>(),_1,bind(Encoder,_2)));
	cout<<s2<<endl;	

	return 0;
}