KookyFlakyHexadecimal created by kiroma - https://repl.it/@kiroma/KookyFlakyHexadecimal

main.cpp

#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
int main(int argc, char** argv) {
  std::vector<int> numbers;
  int input;
  std::fstream ifs(argv[1], std::ios::in);
  while(ifs >> input)numbers.push_back(input);
  if(atoi(argv[2]) > numbers.size()) std::cerr << "Error";
  std::sort(numbers.begin(), numbers.end());
  std::cout << numbers[numbers.size()-atoi(argv[2])];
}

numbers.txt

1 2 4 6 7