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// bind example
#include <iostream> // std::cout
#include <functional> // std::bind
// a function: (also works with function object: std::divides<double> my_divide;)
double my_divide (double x, double y) {return x/y;}
struct MyPair {
double a,b;
double multiply() {return a*b;}
};
int main () {
using namespace std::placeholders; // adds visibility of _1, _2, _3,...
// binding functions:
auto fn_five = std::bind (my_divide,10,2); // returns 10/2
std::cout << fn_five() << '\n'; // 5
auto fn_half = std::bind (my_divide,_1,2); // returns x/2
std::cout << fn_half(10) << '\n'; // 5
auto fn_invert = std::bind (my_divide,_2,_1); // returns y/x
std::cout << fn_invert(10,2) << '\n'; // 0.2
auto fn_rounding = std::bind<int> (my_divide,_1,_2); // returns int(x/y)
std::cout << fn_rounding(10,3) << '\n'; // 3
MyPair ten_two {10,2};
// binding members:
auto bound_member_fn = std::bind (&MyPair::multiply,_1); // returns x.multiply()
std::cout << bound_member_fn(ten_two) << '\n'; // 20
auto bound_member_data = std::bind (&MyPair::a,ten_two); // returns ten_two.a
std::cout << bound_member_data() << '\n'; // 10
return 0;
}
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