pointer to a reference

 #include <iostream>
    using namespace std;

    void foo1(int& x)
    {
    int* p = &x;
    *p = 123;
    }

    void foo2(int* x)
    {
    int** p = &x;
    **p = 345;
    }

    int main(int argc, char* argv[])
    {
    int abc = 0;
    foo1(abc);
    cout << abc << "\n";
    abc = 0;
    foo2(&abc);
    cout << abc << "\n";
    return 0;
    }