header file using a string in a class

i'm working on a project to make a simple blackjack game. so far i am at the point where i should be testing out my card class to see if it's working and everything. i have 3 files, card.h:

Code:

enum cardsuit {HEARTS, DIAMONDS, CLUBS, SPADES};

class card
{
public:
    card();
    void Set_Card(int);
    void Display();
    int Card_Value();
    void Swap_Card(card);

private:
    string description;
    int value;
    cardsuit suit;
};

then there's card.cpp which has all the function def's:

Code:

#include <iostream>
#include <string>
#include "card.h"
using namespace std;

card::card()
{
// initialize card
}

int card::Card_Value()
{
    return value;
}

void card::Display()
{
// display card info
}

void card::Set_Card(int num)
{
// set the card depending on the num
}

void card::Swap_Card(card new_card)
{
// swap current card with the new_card
}

and then my main program so far just tests out the linkage and the display function:

Code:

#include <iostream>
#include <string>
#include "card.h"
using namespace std;

int main()
{
    card cardobject;

    cardobject.Display();

    cin.get();
    return 0;
}

i'm using Dev-Cpp and it tells me "string is used as a type but is not defined as a type" in my card.h file. then it says undeclared variable whenever i try to use the "description" variable... any thoughts? what do i have to do to be able to declare a string variable in a class in a header file? thanks for the help

wait wait wait I think I got it... had to either add "using namespace std" to the header file, or just do a "std::" in front of the string declaration. sorry for such a huge post on such a small fix haha