A program that accepts any number of command line arguments and prints them in alphanumerically sorted order, using a std::set<const char*> to store the elements, then iterate over the set to obtain the sorted result (custom comparator that compares two C-style strings)

CMakeLists.txt

cmake_minimum_required(VERSION 3.15)
project(sets)

set(CMAKE_CXX_STANDARD 17)

add_executable(sets sets.cpp)

sets.cpp

#include <array>
#include <cmath>
#include <iostream>
#include <set>
#include <string.h>
#include <vector>

int main(int argc, char *argv[]) {
  
  std::cout << "Number of arguments " << argc - 1 << std::endl;
  std::vector<const char *> arguments{};

  for (size_t i{1}; i < argc; i++) {
    arguments.emplace_back(argv[i]);
  }

  std::cout << "The vector " << std::endl;
  for (auto &x : arguments)
    std::cout << x << " ";

  auto cmp = [](const char *a, const char *b) {
    
    if (strcmp(a, b) < 0)
      return true;
    else
      return false;
  };

  std::set<const char *, decltype(cmp)> my_set{arguments.cbegin(),
                                               arguments.cend(), cmp};
  std::cout << "\nThe set " << my_set.size() << std::endl;

  for (auto it = my_set.begin(); it != my_set.end(); it++)
    std::cout << *it << " ";

  return 0;
}