cin command to use for inserting value on a function

Question

How could I use cin to insert values for the function?

cin >> addNumber();
cout << addNumber() << endl;

I am not

Answer 1

#include <iostream>

using namespace std;

int addNumber(int x, int y)
{
    int answer = x + y;
    return answer;
}

int main()
{   
    int x,y;
    cout<<"Enter first number"<<endl;
    cin>>x;
    cout<<"Enter second number"<<endl;
    cin>>y;    
    cout<<addNumber(x,y)<<endl;
    return 0;
}

Answer 2

#include <iostream>

int addNumber(int x, int y)
{
    int answer = x + y;
    return answer;
}

int main()
{
    int x,y;
    std::cin >> x >> y;

    std::cout << addNumber(x,y) << std::endl;

    return 0;
}