passing vector object through parameters

[projectnz]

how do i get the vector array vBase2
to pass through the parameter add(vBase2)

add the value 2 to the vector

and then recieve the value in main class

so the output is:

worked
0
Add
1
worked
1

// main class

vector<int> vBase2;

int main()
{
	
		cout << "Worked" << endl;
		//vBase2.push_back(1);
		cout << vBase2.size() << endl;
		system("PAUSE");
		
		firstcl fc;
		fc.Add(vBase2);

		cout << "Worked" << endl;
		cout << vBase2.size() << endl;
		system("PAUSE");
	

	return 0;
}

//header

class firstcl 
{
public:
	void Add(vector<int> vBase2);
};

// cpp

void firstcl::Add(vector<int> vBase2)
{
	
	vBase2.push_back(2);

	cout << "Add" << endl;
	cout << vBase2.size() << endl;
	system("PAUSE");
}

output is:

worked
0
Add
1
worked
0