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Showing content from https://en.cppreference.com/w/cpp/language/../named_req/../algorithm/iter_swap.html below:

std::iter_swap - cppreference.com

template< class ForwardIt1, class ForwardIt2 >
void iter_swap( ForwardIt1 a, ForwardIt2 b );

Swaps the values of the elements the given iterators are pointing to.

If any of the following conditions is satisfied, the behavior is undefined:

• a or b is not dereferenceable.
• *a is not Swappable with *b.

(none)

Constant.

This function template models the semantics of the swap operation given by Swappable. That is, overloads of swap found by ADL and the fall back of std::swap are considered.

template<class ForwardIt1, class ForwardIt2>
constexpr //< since C++20
void iter_swap(ForwardIt1 a, ForwardIt2 b)
{
    using std::swap;
    swap(*a, *b);
}

The following is an implementation of selection sort in C++.

#include <algorithm>
#include <iostream>
#include <random>
#include <string_view>
#include <vector>
 
template<class ForwardIt>
void selection_sort(ForwardIt begin, ForwardIt end)
{
    for (ForwardIt it = begin; it != end; ++it)
        std::iter_swap(it, std::min_element(it, end));
}
 
void println(std::string_view rem, std::vector<int> const& v)
{
    std::cout << rem;
    for (int e : v)
        std::cout << e << ' ';
    std::cout << '\n';
}
 
template<int min, int max>
int rand_int()
{
    static std::uniform_int_distribution dist(min, max);
    static std::mt19937 gen(std::random_device{}());
    return dist(gen);
}
 
int main()
{
    std::vector<int> v;
    std::generate_n(std::back_inserter(v), 20, rand_int<-9, +9>);
 
    std::cout << std::showpos;
    println("Before sort: ", v);
    selection_sort(v.begin(), v.end());
    println("After sort:  ", v);
}

Possible output:

Before sort: -9 -3 +2 -8 +0 -1 +8 -4 -5 +1 -4 -5 +4 -9 -8 -6 -6 +8 -4 -6 
After sort:  -9 -9 -8 -8 -6 -6 -6 -5 -5 -4 -4 -4 -3 -1 +0 +1 +2 +4 +8 +8

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

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