trying to make a file to hold a class

[morngrym]

ok so I have been trying to split into a separate file one of my classes but every time I try to use a string [some name] it errors the string and is so confusing. this code shows me what I want but I can not get it split into separate files and work. Anyone able to help with this? if someone could show me the critter.h file, critter.cpp and main.cpp.
thanks

#include<iostream>
#include<string>

using namespace std;

class critter
{
protected:
	int HP;
	string name;

public:
	void setname(string n);
	string getname();
	void sethp(int h);
	int gethp();
	critter();
	~critter();
};
critter::critter(): HP(6), name("rat")
{}
critter::~critter()
{}
void critter::setname(string n)
{
	name = n;
}
string critter::getname()
{
	return name;
}
int critter::gethp()
{
	return HP;
}
void critter::sethp(int h)
{
	HP=h;
}

class goblin: public critter
{
public:
	goblin();

};
goblin::goblin()		// i dont know how to get this goblin to load inital values
{
	goblin::sethp(10), goblin::setname("goblin");
}




int main()
{
	critter* mob;
	mob=new critter[3];
	for(int i = 0; i < 3; ++i)
	{mob[i].~critter();}
	mob[0]=goblin();
	mob[1]=critter();
	cout << mob[0].gethp() << " hp's" << endl;
	cout << mob[0].getname() << " name\n";
	cout << mob[1].gethp() << " hp's" << endl;
	cout << mob[1].getname() << " name\n";

	system("pause");
	return 0;
}