/* Liet ke tat ca các hoan vi cua 1 chuoi */
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;

void swap ( char &r, char &c )
{
        char temp = r;
        r = c;
        c = temp;
}

void permutation_string ( string s, string pre )
{
        int n = s.length();
        if ( n == 1 )
        {
                cout << pre + s << endl;
        }
        else
        {
                for ( int i = 0; i < n; i++ )
                {
                        swap ( s[i], s[0] );
                        permutation_string ( s.substr (1, n-1 ), pre + s.substr (0,1) );
                        
                        
                        cout << "--------------------------";
                        cout << endl;
                        cout << " N equal to  : " << n << endl;
                        cout << "s.substr (1, n-1 ) is :  " <<  s.substr (1, n-1 ) << endl;
                        cout << "pre is :  " <<  pre   << endl;
                        cout << "s.substr (0,1) is :  " << s.substr (0,1) << endl;
                }
        }
}
void main()
{
        string a_string;
        cout << "Enter a string: "; cin >> a_string;
        
        print ( a_string, " ");
        
cin >> a_string;
}