Generating powesets of a vector

Question

I am currently trying to write a function which will allow me to create the powerset of a vector. I currently have a vector of objects and an empty vector of vectors. I looked around online, and found a recursive algorithm, but was unable to get it to work in my case.

Algorithm:

void Game::PowersetRec(vector <Die> & s, int k, int m, int n) {
    // Recursively builds a vector which is the powerset of the input vector
    if (m <= n) {
        s[k+1].pips = m ;
        powerset.push_back(s) ;
        PowersetRec(s, k+1, m+1, n) ; /* with m */
        PowersetRec(s, k, m+1, n) ; /*  without m */
    }
}

.

PowersetRec(rolledDice, 0, rolledDice[0].pips, rolledDice[rolledDice.size() - 1].pips);

powerset is my vector of vectors and rolledDice is a vector of Die objects which have a pips attribute (which is an integer).

When I print out powerset I get this (sample):

1, 1, 4, 6, 4, 6
1, 1, 2, 6, 4, 6
1, 1, 2, 3, 4, 6
1, 1, 2, 3, 4, 5

Which makes sense to me given the algorithm, but isn't the powerset, meaning I don't know how the original algorithm worked.

Edit: This answer Seems useful, but I cannot get the code listed (combinations) to compile in GCC.

Answer 1

I was able to answer the question via: the different combinations of a vector's values

I simply changed char to my die object.

Edit: Full code below.

void Game::PowersetGen(vector <Die> & v) {
for (int counter = 1; counter < (1 << v.size()); ++counter) {
        vector <Die> combination;
        for (int i = 0; i < v.size(); ++i)
        {
            if (counter & (1 << i))
                combination.push_back(v[i]);
        }

        powerset.push_back(combination);
    }
}

Simple clarifying edit: <Die> is just the name of the object in my vector, ideally this function would be templated to use any data type.