print all combinations of 2D string array

printAllCombinationsString.cpp

// author : huklee
// source : JTD 2017-03-05
// print all combinations of string 2D list

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

string print_combination(vector<int> &index_list, vector<vector<string> > &v){
	string s = "";

	for (int i=0; i < index_list.size(); i++)
		s += v[i][index_list[i]];
	return s;
}

bool is_equal(vector<int> &index_list, vector<int> &end_cond){
	for (int i=0; i < index_list.size(); i++)
		if (index_list[i] != end_cond[i])
			return false;
	return true;
}

void increment(vector<int> &index_list, vector<vector<string> > &v){
	for (int i=index_list.size() - 1; i >= 0; i--){
		index_list[i]++;
		if (index_list[i] == v[i].size()){
			index_list[i] = 0;
			continue;
		}
		break;
	}
}

void printAll(vector<vector<string> > &v){
	vector<int> index_list(v.size(), 0);
	vector<int> end_cond;
	for (int i=0; i < v.size(); i++)
		end_cond.push_back(v[i].size() - 1);

	while (true){
	  	// print each combination
		cout << print_combination(index_list, v) << endl;
		if (is_equal(index_list, end_cond))
			break;
     
		// increment the combination index
		increment(index_list, v);
	}
}

int main(){
	vector<vector<string> > vs{{"1","2","3"},{"4","5","6"},{"7","8","9"}};
	printAll(vs);

	return 0;
}