std::ranges::stable_sort

#include <algorithm>
#include <array>
#include <functional>
#include <iomanip>
#include <iostream>

void print(const auto& seq)
{
    for (const auto& elem : seq)
        std::cout << elem << ' ';
    std::cout << '\n';
}

struct Particle
{
    std::string name; double mass; // MeV
    friend std::ostream& operator<<(std::ostream& os, const Particle& p)
    {
        return os << '\n' << std::left << std::setw(8) << p.name << " : " << p.mass;
    }
};

int main()
{
    std::array s{5, 7, 4, 2, 8, 6, 1, 9, 0, 3};

    // sort using the default operator<
    std::ranges::stable_sort(s);
    print(s);

    // sort using a standard library compare function object
    std::ranges::stable_sort(s, std::ranges::greater());
    print(s);

    // sort using a custom function object
    struct
    {
        bool operator()(int a, int b) const { return a < b; }
    } customLess;
    std::ranges::stable_sort(s.begin(), s.end(), customLess);
    print(s);

    // sort using a lambda expression
    std::ranges::stable_sort(s, [](int a, int b) { return a > b; });
    print(s);

    // sort with projection
    Particle particles[]
    {
        {"Electron", 0.511}, {"Muon", 105.66}, {"Tau", 1776.86},
        {"Positron", 0.511}, {"Proton", 938.27}, {"Neutron", 939.57}
    };
    print(particles);
    std::ranges::stable_sort(particles, {}, &Particle::name); //< sorts by name
    print(particles);
    std::ranges::stable_sort(particles, {}, &Particle::mass); //< sorts by mass
    print(particles);
}

Вывод:

0 1 2 3 4 5 6 7 8 9
9 8 7 6 5 4 3 2 1 0
0 1 2 3 4 5 6 7 8 9
9 8 7 6 5 4 3 2 1 0

Electron : 0.511
Muon     : 105.66
Tau      : 1776.86
Positron : 0.511
Proton   : 938.27
Neutron  : 939.57

Electron : 0.511
Muon     : 105.66
Neutron  : 939.57
Positron : 0.511
Proton   : 938.27
Tau      : 1776.86

Electron : 0.511
Positron : 0.511
Muon     : 105.66
Proton   : 938.27
Neutron  : 939.57
Tau      : 1776.86