Answer 1

If you need the function to only accept one argument of type Vector, then the general solution is to truncate the vector on each recursion.
{1,2,3,4,5,6}
print last value
remove last value from vector
pass new vector {1,2,3,4,5} to recursive call
Run till vector is empty.
You need to understand how to create a new vector from an old vector using iterators, and where the iterators point to.
https://code.sololearn.com/cbSxLu61HI7k/?ref=app

Answer 2

Here's my alternative implementation of what Hatsy Rei has just explained
void print(vector<int>& v){
if (v.size() == 0) return;
cout << v.back() << " ";//print the last element
v.pop_back();//remove that last element
print(v); //repeat
}
int main(){
vector<int> v={1,2,3,4,5,6};
print(v);// 6 5 4 3 2 1
}