dude.. gist it

gistfile1.c++

double any_op(double, double, std::function<double(double,double)>);

int main()
{ 
 std::function<double(double,double)> add = [](double a, double b) -> double { return a+b; };
 std::function<double(double,double)> sub = [](double a, double b) -> double { return a-b; };

 printf("5 + 10 = %0.2f\n", any_op(5., 10., add));
 printf("5 - 10 = %0.2f\n", any_op(5., 10., sub));

 return 0;
}

double any_op(double a, double b, std::function<double(double,double)> op) {
 return op(a,b);
}