Combinations of string

Create a set containing the combination of all non-empty sub-strings.  Eg:  combination of string "abc" is {a, ab, abc, bc, b, c}

/*

 * StringCombinations.cpp

 *

 *  Created on: Apr 18, 2012

 *      Author: Kiran Hegde

 */

#include <iostream>

#include <string>

#include <vector>

using namespace std;

void combine(string prefix, string rest, vector<string> &output) {

    if (prefix.size() > 0)

        output.push_back(prefix);

    for (unsigned int  i=0; i<rest.size(); i++) {

        combine(prefix + rest[i], rest.substr(i+1), output);

    }

}

/**

 * Test the function

 */

int main() {

    string input("abcd");

    vector<string> combs;

    combine("", input, combs);

    cout << "Combinations: " << endl;

    for (unsigned int i=0; i<combs.size(); i++) {

        cout << combs[i] << endl;

    }

}