C++:How to pass reference-to-function into another function?

Question

I have been reading about function pointers and about using them as parameters for other functions. My question is how would you pass a function by reference without using p

Answer 1

#include 
using namespace std;

void doCall( void (&f)(int) )
{
    f( 42 );
}

void foo( int x )
{
    cout << "The answer might be " << x << "." << endl;
}

int main()
{
    doCall( foo );
}

Cheers & hth.,