#include #include #include // Max voters and candidates #define MAX_VOTERS 100 #define MAX_CANDIDATES 9 // preferences[i][j] is jth preference for voter i int preferences[MAX_VOTERS][MAX_CANDIDATES]; // Candidates have name, vote count, eliminated status typedef struct { string name; int votes; bool eliminated; } candidate; // Array of candidates candidate candidates[MAX_CANDIDATES]; // Numbers of voters and candidates int voter_count; int candidate_count; // Function prototypes bool vote(int voter, int rank, string name); void tabulate(void); bool print_winner(void); int find_min(void); bool is_tie(int min); void eliminate(int min); int main(int argc, string argv[]) { // Check for invalid usage if (argc < 2) { printf("Usage: runoff [candidate ...]\n"); return 1; } // Populate array of candidates candidate_count = argc - 1; if (candidate_count > MAX_CANDIDATES) { printf("Maximum number of candidates is %i\n", MAX_CANDIDATES); return 2; } for (int i = 0; i < candidate_count; i++) { candidates[i].name = argv[i + 1]; candidates[i].votes = 0; candidates[i].eliminated = false; } voter_count = get_int("Number of voters: "); if (voter_count > MAX_VOTERS) { printf("Maximum number of voters is %i\n", MAX_VOTERS); return 3; } // Keep querying for votes for (int i = 0; i < voter_count; i++) { // Query for each rank for (int j = 0; j < candidate_count; j++) { string name = get_string("Rank %i: ", j + 1); // Record vote, unless it's invalid if (!vote(i, j, name)) { printf("Invalid vote.\n"); return 4; } } printf("\n"); } // Keep holding runoffs until winner exists while (true) { // Calculate votes given remaining candidates tabulate(); // Check if election has been won bool won = print_winner(); if (won) { break; } // Eliminate last-place candidates int min = find_min(); bool tie = is_tie(min); // If tie, everyone wins if (tie) { for (int i = 0; i < candidate_count; i++) { if (!candidates[i].eliminated) { printf("%s\n", candidates[i].name); } } break; } // Eliminate anyone with minimum number of votes eliminate(min); // Reset vote counts back to zero for (int i = 0; i < candidate_count; i++) { candidates[i].votes = 0; } } return 0; } // Record preference if vote is valid bool vote(int voter, int rank, string name) { // TODO for (int i = 0; i < candidate_count; i++) { if (strcmp(name, candidates[i].name) == 0) { preferences[voter][rank] = i; return true; } } return false; } // Tabulate votes for non-eliminated candidates void tabulate(void) { // TODO for (int j = 0; j < voter_count; j++) { for (int i = 0; i < candidate_count; i++) { if (candidates[preferences[j][i]].eliminated == false) { candidates[preferences[j][i]].votes++; break; } } } return; } // Print the winner of the election, if there is one bool print_winner(void) { //TODO //itera int winner = -1; bool tie = false; for (int i = 0; i < candidate_count; i++) { if (candidates[i].eliminated == false && candidates[i].votes > voter_count / 2) { if (winner == -1) { winner = i; } else { tie = true; } } } if (winner > -1 && tie == false) { printf("%s\n", candidates[winner].name); return true; } return false; } // Return the minimum number of votes any remaining candidate has int find_min(void) { // iterating over all candidate votes int min_votes = -1; for (int i = 0; i < candidate_count; i++) { //checking if this is the first not-eliminated candidate and setting initial lowest votes value if (min_votes == -1 && candidates[i].eliminated == false) { min_votes = i; } //comparing previously seen min votes vs current candidate if (candidates[i].votes < candidates[min_votes].votes && candidates[i].eliminated == false) { min_votes = i; } } //returns minimum number of votes return candidates[min_votes].votes; } // Return true if the election is tied between all candidates, false otherwise bool is_tie(int min) { //iterating through candidate votes, when candidate votes are bigger than min return false, tie is not possible for (int i = 0; i < candidate_count; i++) { if (candidates[i].votes > min) { return false; } } return true; } // Eliminate the candidate (or candidates) in last place void eliminate(int min) { // iterating over all candidates and comparing who has the min votes, than setting his eliminated state to true for (int i = 0; i < candidate_count; i++) { if (candidates[i].votes == min) { candidates[i].eliminated = true; } } return; }