int f(int &x, int c)
{
c = c-1;
if (c == 0) return 1;
x = x +1;
return f(x,c) * x;
}
What is the return value of $f(p,p),$ if the value of $p$ is initialized to $4$ before the call$?$ Note that the first parameter is passed by
reference, whereas the second parameter is passed by value.