It makes switch be able to treat string.

stringSwitch.cpp

// Hash function by http://blog.naver.com/PostView.nhn?blogId=devmachine&logNo=220952781191
// Hash const by http://www.sysnet.pe.kr/Default.aspx?mode=2&sub=0&pageno=0&detail=1&wid=1223

#include <iostream>

using namespace std;

constexpr unsigned int HashCode(const char* str) {
	return str[0] ? static_cast<unsigned int>(str[0]) + 0xEDB8832Full * HashCode(str + 1) : 8603;
}

#define STRING_SWITCH_START(x) {string _SWITCHx_ = x; switch(HashCode(x.c_str()))
#define S_CASE_START(x) case HashCode(x): if (_SWITCHx_ == x) {
#define S_CASE_END } else { throw logic_error("[!] Error. Hash collision!"); } break
#define STRING_SWITCH_END }

int main() {
	string test = "bye";

	STRING_SWITCH_START(test) {
		S_CASE_START("hello") cout << "Hello World." << endl; S_CASE_END;
		S_CASE_START("bye") cout << "Bye Bye~" << endl; S_CASE_END;
		S_CASE_START("apple") cout << "Apple is fresh." << endl; S_CASE_END;
		S_CASE_START("orange") cout << "Orange is sour." << endl; S_CASE_END;
		S_CASE_START("melon") cout << "Melon is sweet." << endl; S_CASE_END;
	}STRING_SWITCH_END;

	return EXIT_SUCCESS;
}