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CS50's Introduction to Computer Science on Edx: Supplementary resource

CS50 threads to aide as a supplementary resource

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#include <cs50.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

// Max voters and candidates
#define MAX_VOTERS 100
#define MAX_CANDIDATES 9

// preferences[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.name = argv;
        candidates.votes = 0;
        candidates.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("%i, %i, %s\n", i + 1, j + 1, candidates[preferences[j]].name);
        }
   }


//printf("complete");


tabulate();
}


    /*

    // 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.eliminated)
                {
                    printf("%s\n", candidates.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.votes = 0;
        }
    }
    return 0;
}

*/

// Record preference if vote is valid
bool vote(int voter, int rank, string name)
{
    //printf("voter no (via local function taking value of voter as argument).: %i, rank selected (via local function taking value of rank as argument) %i\n", voter + 1, rank + 1);
    for (int t = 0; t < candidate_count; t++)
        {
            if(strcmp(name, candidates[t].name) == 0)
            {
            preferences[voter][rank] = t;
            //printf("preference of voter no. %i for rank %i is %s\n", voter + 1, rank + 1, candidates[t].name);
            return 4;
            }
        }
    return 0;
}



// Tabulate votes for non-eliminated candidates
void tabulate(void)
{
    int vc = 0;
    int cc = 0;
    for (vc = 0; vc < voter_count; vc++)
    {
        //candidates[cc].votes = candidates[preferences[vc][0]].votes + 1
            printf("no. 1 is %s", candidates[preferences[vc][0]].name);
            for (cc = 0; cc < candidate_count; cc++)
            {
                if (candidates[cc].name == candidates[preferences[vc][0]].name)
                {
                candidates[cc].votes = candidates[cc].votes + 1;
                printf("candidate vote is %i", candidates[cc].votes);
                }
            }
            //int z = max(candidates[cc].votes);
           // printf("%i", max(candidates[cc].votes));

    }

        //for (vc = 0; vc < voter_count; vc++)
        //{
            //for (cc = 0; cc < candidate_count; cc++)
            //{
                //if (candidates[cc].name == preferences[vc][cc])
            //}
        //}



   return;
}

/*

// Print the winner of the election, if there is one
bool print_winner(void)
{
    // TODO
    return false;
}

// Return the minimum number of votes any remaining candidate has
int find_min(void)
{
    // TODO
    return 0;
}

// Return true if the election is tied between all candidates, false otherwise
bool is_tie(int min)
{
    // TODO
    return false;
}

// Eliminate the candidate (or candidates) in last place
void eliminate(int min)
{
    // TODO
    return;
}
*/

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