CandidateSet CandidateSet::getCandidateTrees(double score) {
CandidateSet res;
for (CandidateSet::iterator it = begin(); it != end(); it++) {
if (abs(it->first - score) < 0.1) {
res.insert(*it);
}
}
return res;
}
CandidateSet CandidateSet::getBestCandidateTrees(int numTrees) {
CandidateSet res;
if (numTrees >= size() || numTrees == 0)
numTrees = (int) size();
for (reverse_iterator rit = rbegin(); rit != rend() && numTrees > 0; rit++, numTrees--) {
res.insert(*rit);
}
return res;
}
//Print the message followed by all the entries in the CandidateTally, in
// the order specified by has_higher_priority: i is printed before j, if
// has_higher_priority(i,j) returns true: sometimes alphabetically by candidate,
// other times by decreasing votes for the candidate.
//Use a "->" to separate the candidate name from the number of votes they
// received.
void print_tally(std::string message, const CandidateTally& tally, bool (*has_higher_priority)(const TallyEntry& i,const TallyEntry& j)) {
CandidateSet candidateSet;
for (const auto& kv : tally) {
candidateSet.insert(kv.first);
}
TallyEntryPQ tallyPQ(*has_higher_priority);
tallyPQ.enqueue_all(tally);
std::cout << message << ": still in election = " << candidateSet << std::endl;
for (const TallyEntry& tallyEntry : tallyPQ) {
std::cout << " " << tallyEntry.first << " -> " << tallyEntry.second << std::endl;
}
std::cout << std::endl;
}
//Prompt the user for a file, create a voter preference Map, and print it.
//Determine the Set of all the candidates in the election, from this Map.
//Repeatedly evaluate the ballot based on the candidates (still) in the
// election, printing the vote count (tally) two ways: with the candidates
// (a) shown alphabetically increasing and (b) shown with the vote count
// decreasing (candidates with equal vote counts are shown alphabetically
// increasing); from this tally, compute which candidates remain in the
// election: all candidates receiving more than the minimum number of votes;
// continue this process until there are less than 2 candidates.
//Print the final result: there may 1 candidate left (the winner) or 0 left
// (no winner).
int main() {
try {
std::ifstream text_file;
ics::safe_open(text_file,"Enter the name of a file with voter preferences","votepref1.txt");
std::cout << std::endl;
const Preferences prefs = read_voter_preferences(text_file);
print_voter_preferences(prefs);
std::cout << std::endl;
CandidateSet candidateSet;
for (const auto& kv : prefs) {
for (const std::string& candidate : kv.second) {
candidateSet.insert(candidate);
}
}
CandidateTally tally = evaluate_ballot(prefs, candidateSet);
int ballot = 1;
while (candidateSet.size() > 1) {
std::stringstream ss;
ss << ballot++;
print_tally("Vote count on ballot #" + ss.str() +
" with candidates in alphabetical order", tally, alphabetic_gt);
print_tally("Vote count on ballot #" + ss.str() +
" with candidates in numerical order", tally, numeric_gt);
candidateSet = remaining_candidates(tally);
tally = evaluate_ballot(prefs, candidateSet);
}
if (candidateSet.size() == 0) {
std::cout << "No winner" << std::endl;
} else {
std::string winner;
for (const std::string& candidate : candidateSet) {
winner += candidate + " and ";
}
std::cout << "Winner is " << winner.substr(0, winner.length()-5) << std::endl;
}
} catch (ics::IcsError& e) {
std::cout << e.what() << std::endl;
}
return 0;
}
//Return the Set of candidates who are still in the election, based on the
// tally of votes: compute the minimum number of votes and return a Set of
// all candidates receiving more than that minimum; if all candidates
// receive the same number of votes (that would be the minimum), the empty
// Set is returned.
CandidateSet remaining_candidates(const CandidateTally& tally) {
CandidateSet result;
if (!tally.empty()) {
int min = -1;
for (const TallyEntry& entry : tally) {
if (min == -1 || entry.second < min) {
min = entry.second;
}
}
for (const TallyEntry& entry : tally) {
if (entry.second > min) {
result.insert(entry.first);
}
}
}
return result;
}
