How to call a function several times in C++ with different parameters

Question

I have the next code:

object a,b,c;
fun (a);
fun (b);
fun (c);

I wonder if it is there any way to do something similar in C++98 or C++11 to:

call_fun_with (fun, a, b, c);

Thanks

Answer 1

Here a variadic template solution.

#include <iostream>

template < typename f_>
void fun( f_&& f ) {}

template < typename f_, typename head_, typename... args_>
void fun( f_ f, head_&& head, args_&&... args) {
    f( std::forward<head_>(head) );
    fun( std::forward<f_>(f), std::forward<args_>(args)... );
}

void foo( int v ) {
    std::cout << v << " ";
}

int main() {
  int a{1}, b{2}, c{3};
  fun(foo, a, b, c );
}

Answer 2

You may use the following using variadic template:

template <typename F, typename...Ts>
void fun(F f, Ts&&...args)
{
    int dummy[] = {0, (f(std::forward<Ts>(args)), 0)...};
    static_cast<void>(dummy); // remove warning for unused variable
}

or in C++17, with folding expression:

template <typename F, typename...Ts>
void fun(F&& f, Ts&&...args)
{
    (static_cast<void>(f(std::forward<Ts>(args))), ...);
}

Now, test it:

void foo(int value) { std::cout << value << " "; }

int main(int argc, char *argv[])
{
    fun(foo, 42, 53, 65);

    return 0;
}