C++产生不重复的随机数

#include <iostream>
#include <algorithm>
#include <vector>
#include <ctime>
using namespace std;

int main()
{
  srand ( unsigned ( time (NULL) ) );
  vector<int> myvector;
  vector<int>::iterator it;
  for (int i=1;i<=13;i++)
  {
   myvector.push_back(i);
  }

  random_shuffle ( myvector.begin(), myvector.end() );

  for (it=myvector.begin();it!=myvector.end();++it)
  {
    cout<<" "<<*it;
  }
}