C++ When my code asks for my full name it only gets my first name and not last

Hello I am new to C++ and when I tried to make my code ask for my full name and then print it, it only displayed my first name. Here is an example of my code:

#include <iostream>
#include <string>

using namespace std;

int main()
{
	string fullname;
	cout << "What is your full name?" << endl;
	cin >> fullname;
	cout << "Hello " << fullname << endl;
}