powerSetRecursiveCharArr.cpp

#include <iostream>
#include <vector>
#include <string>

using namespace std;

vector<char*>* powerSet(char* src) {
	if (strlen(src) == 0) {
		vector<char*>* ret = new vector<char*>();
		ret->push_back("");
		return ret;
	}

	char digit = src[0];
	src++;
	
	vector<char*>* res1 = powerSet(src);
	vector<char*>* res2 = new vector<char*>();

	for (int i=0 ; i < res1->size() ; i++) {
		char* str = new char[strlen(res1->at(i))+1];
		str[0] = digit;

		// duplicate
		strcpy(str+1, res1->at(i));
		res2->push_back(str);
	}

	// concatenating vectors
	res1->insert( res1->end(), res2->begin(), res2->end() );

	return res1;
}

int main() {
	vector<char*>* res = powerSet("abc");

	for (int i=0 ; i < res->size() ; i++) {
		cout << res->at(i) << endl;
	}
}