std::iter_swap

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Example

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selection_sort: <ForwardIt>(begin: ForwardIt, end: ForwardIt) = {
    for begin..<end do (it: ForwardIt) {
        std::iter_swap(it, std::min_element(it, end));
    }
}

print_vec: (rem: std::string_view, v: std::vector<int>) = {
    std::cout << rem;
    for v do (e: int) {
        std::cout << "(e)$ ";
    }
    std::cout << '\n';
}

rand_int: <min: int, max: int>() -> int = {
    dist: std::uniform_int_distribution = (min, max);
    dev:  std::random_device = ();
    gen:  std::mt19937 = (dev());
    return dist(gen);
    _ = gen;
}

main: () = {
    v: std::vector<int> = ();
    std::generate_n(std::back_inserter(v), 20, rand_int<-9, +9>);

    std::cout << std::showpos;
    print_vec("Before sort: ", v);
    selection_sort(v.begin(), v.end());
    print_vec("After sort:  ", v);
}

Possible output

Before sort: 7 7 5 -1 -9 -6 9 -9 8 -2 5 0 -7 -5 4 3 -9 0 2 1 
After sort:  -9 -9 -9 -7 -6 -5 -2 -1 0 0 1 2 3 4 5 5 7 7 8 9