Knuth Shuffle(Fisher-Yates Shuffle)を実装。

knuth_shuffle.cpp

#include <iostream>
#include <vector>
#include <random>
#include <cmath>

// knuth shuffle
void shuffle(std::vector<int>& ary){
  std::random_device rd;
  std::mt19937 mt(rd());
  long N = ary.size();
  for(long i = N-1; i >= 0; i--){
    //long r = std::floor(mt()*(i+1));
    std::uniform_int_distribution<> rnd(0, i);
    long r = rnd(mt);
    long t = ary[i];
    ary[i] = ary[r];
    ary[r] = t;
  }
}

void showData(const std::vector<int>& ary){
  for(auto el : ary){
    std::cout << el << " ";
  }
  std::cout << std::endl;
}

int main(void){
  using std::vector;
  const long N = 1e1;
  vector<int> ary(N);
  //for(auto& el : ary) el = i
  std::iota(begin(ary), end(ary), 1);
  [&](){for(auto el:ary)std::cout<<el<<" "; std::cout<<std::endl;}();//C++11 practice
  //showData(ary);
  shuffle(ary);
  showData(ary);
  return 0;
}