swap Function <functional>
Swaps two function objects.
template<class Fty>
void swap(function<Fty>& f1,
function<Fty>& f2);
Parameters
Fty
The type controlled by the function objects.f1
The first function object.f2
The second function object.
Remarks
The function returns f1.swap(f2).
Example
// std_tr1__functional__swap.cpp
// compile with: /EHsc
#include <functional>
#include <iostream>
int neg(int val)
{
return (-val);
}
int main()
{
std::function<int (int)> fn0(neg);
std::cout << std::boolalpha << "empty == " << !fn0 << std::endl;
std::cout << "val == " << fn0(3) << std::endl;
std::function<int (int)> fn1;
std::cout << std::boolalpha << "empty == " << !fn1 << std::endl;
std::cout << std::endl;
swap(fn0, fn1);
std::cout << std::boolalpha << "empty == " << !fn0 << std::endl;
std::cout << std::boolalpha << "empty == " << !fn1 << std::endl;
std::cout << "val == " << fn1(3) << std::endl;
return (0);
}
empty == false val == -3 empty == true empty == true empty == false val == -3
Requirements
Header: <functional>
Namespace: std