Example
#include <iostream>
#include <functional>
using std::placeholders::_1; // to be used in std::bind example
int stdf_foobar (int x, std::function<int(int)> moo)
{
return x + moo(x); // std::function moo called
}
int foo (int x) { return 2+x; }
int foo_2 (int x, int y) { return 9*x + y; }
int main()
{
int a = 2;
/* Function pointers */
std::cout << stdf_foobar(a, &foo) << std::endl; // 6 ( 2 + (2+2) )
// can also be: stdf_foobar(2, foo)
/* Lambda expressions */
/* An unnamed closure from a lambda expression can be
* stored in a std::function object:
*/
int capture_value = 3;
std::cout << stdf_foobar(a,
[capture_value](int param) -> int { return 7 + capture_value * param; })
<< std::endl;
// result: 15 == value + (7 * capture_value * value) == 2 + (7 + 3 * 2)
/* std::bind expressions */
/* The result of a std::bind expression can be passed.
* For example by binding parameters to a function pointer call:
*/
int b = stdf_foobar(a, std::bind(foo_2, _1, 3));
std::cout << b << std::endl;
// b == 23 == 2 + ( 9*2 + 3 )
int c = stdf_foobar(a, std::bind(foo_2, 5, _1));
std::cout << c << std::endl;
// c == 49 == 2 + ( 9*5 + 2 )
return 0;
}
