全排列递归算法

#include <iostream>
#include <string>
using namespace std;

void swap(char &a, char &b)
{
    char temp;
    temp = a;
    a = b;
    b = temp;
}

void perm(char* a, int k, int n, int &count)
{
    if( k < n )
    {
        for(int i = k; i < n ; ++i)
        {
            swap(a[k], a[i]);
            perm(a, k + 1, n, count);
            swap(a[k], a[i]);
        }
    }
    else
    {
        count++;
        for(int i = 0; i < n; ++i)
        {
            cout << a[i];
        }

        cout << endl;

    }
}

int main()
{
    string str;
    while(cin >> str)
    {
        int count = 0;
        perm((char*)str.c_str(), 0, str.size(), count);

        cout << "total: " << count << endl;
    }

    return 0;
}