c++ 형변환 함수

#include <iostream>  
#include <string>  
using namespace std;

int main()
{
	cout << "int -> string " << endl;
	int i = 10;
	cout << i + i << endl;
	string s = to_string(i);
	cout << s + s << endl << endl;

	cout << "string -> int " << endl;
	string str = "123";
	cout << str + str << endl;
	int _int = stoi(str);
	cout << _int + _int << endl << endl;

	cout << "const char* -> string " << endl;
	const char* ss = "1234";
	cout << ss + 1 << endl;
	int ii = atoi(ss);
	cout << i + i << endl << endl;

	cout << "string -> const char* " << endl;
	string sss = "12345";
	cout << sss + sss << endl;
	const char* constr = sss.c_str();
	cout << constr + 1 << endl << endl;

	return 0;
}