/* FILE: randPerm.cpp   last change: 22-May-2012   author: Romeo Rizzi
 * This program generates a random permutation.
 * Usage syntax:
 *   > randPerm
 */

#include <iostream>
#include <stdlib.h>
#include <time.h>
#include <assert.h>

using namespace std;

inline void swap(int &a, int &b) { int tmp = a; a = b; b = tmp; }

void generaPerm_random_uniform(int *perm, int n) {
   for(int i=n; i > 1; i--)
     swap( perm[i], perm[ (rand() % i) + 1 ] );
}


main(int argc, char** argv) {
  srand (time(NULL));   // initialize the pseudo-random generator

  int n; cout << "Quanti oggetti vuoi permutare: ";
   cin >> n;

  int perm[n+1];
  for(int i = 1; i <= n; i++)  perm[i] = i;

  generaPerm_random_uniform(perm, n);

  for(int i = 1; i <= n; i++)  cout <<  " " << perm[i];
  cout << endl;
}