Get all combinations without duplicates

Question

Give all possible combinations of a string without duplicates in c++. Example input: \"123\" and output combinations will be:

 1,12,123,13,2,23,3.

Answer 1

Thought I'd add an answer from @Caninonos in the comments. I just simplified it slightly removing templates etc. This is a recursive solution.

#include 
#include 
using namespace std;

void get_substrings_aux(vector& subs, string str ,unsigned int cnt) {

    if(cnt == str.size())
    return;

    int n = subs.size();
    char c = str[cnt];
    for(int i = 0 ; i < n ; ++i) {
        subs.push_back(subs[i] + c);
        cout << subs[i] + c << endl;
    }
    get_substrings_aux(subs, str, ++cnt);
}

vector get_substrings(const string& str) {
    vector subs(1);
    int cnt=0;
    get_substrings_aux(subs, str, cnt);
    subs.erase(subs.begin());
    return subs;
}

int main() {
    string str("1234");
    vector subs = get_substrings(str);
    return 0;
}