The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017
#include <functional>
void forUpTo(int n, std::function<void(int)> f)
{
for (int i = 0; i != n; ++i)
{
f(i); // call passed function f for i
}
}