std::pair<T1,T2>:: swap

Swaps first with other.first and second with other.second , as if by using std:: swap ; swap ( first, other. first ) ; swap ( second, other. second ) ; .

Parameters

Return value

(none)

Exceptions

Example

#include <iostream>
#include <utility>
#include <string>
int main()
{
    std::pair<int, std::string> p1(10, "test"), p2;
    p2.swap(p1);
    std::cout << "(" << p2.first << ", " << p2.second << ")\n";
 
#if __cpp_lib_ranges_zip >= 202110L
    // Using the C++23 const qualified swap overload
    // (swap is no longer propagating pair constness)
    int i1 = 10, i2{};
    std::string s1("test"), s2;
    const std::pair<int&, std::string&> r1(i1, s1), r2(i2, s2);
    r2.swap(r1);
    std::cout << "(" << i2 << ", " << s2 << ")\n";
#endif
}

(10, test)
(10, test)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also