示例
#include <iostream>
#include <functional>
using std::placeholders::_1; //在std::bind示例中使用
int stdf_foobar (int x, std::function<int(int)> moo)
{
return x + moo(x); //std::functionmoo称为
}
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））
//也可以是：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;
//结果：15==值+（7*capture_value*值）==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;
}
