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 

using namespace std;

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

int main()
{   
    int x,y;
    cout<<"Enter first number"<>x;
    cout<<"Enter second number"<>y;    
    cout<