plurality.c

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

#define MAX 9  // max number of candidates

typedef struct  // candidates have name and vote count
{
    string name;
    int votes;
}
candidate;

candidate candidates[MAX];  // array of candidates

int candidate_count;  // number of candidates

bool vote(string name);  // function prototypes
void print_winner(void);

int main(int argc, string argv[])
{
    if (argc < 2)  // check for invalid usage
    {
        printf("Usage: plurality [candidate ...]\n");
        return 1;
    }

    candidate_count = argc - 1;  // populate array of candidates
    if (candidate_count > MAX)
    {
        printf("Maximum number of candidates is %i\n", MAX);
        return 2;
    }
    for (int i = 0; i < candidate_count; i++)
    {
        candidates[i].name = argv[i + 1];
        candidates[i].votes = 0;
    }

    int voter_count = get_int("Number of voters: ");

    for (int i = 0; i < voter_count; i++)  // loop over all voters
    {
        string name = get_string("Vote: ");

        if (!vote(name))  // check if vote() returns FALSE, if so...
        {
            printf("Invalid vote.\n");
        }
    }
    print_winner(); // display winner of election
}

bool vote(string name)  // update vote totals given a new vote
{
    for (int i = 0; i < candidate_count; i++)   // iterate through each of the candidates[] one by one
    {
        if (strcmp(name, candidates[i].name) == 0)  // compare the strings "name" and candidate[i].name. IF they match...
        {
            candidates[i].votes++;  // add a value of 1 to the candidates votes
            return true;  // return TRUE, indicating the vote is valid
        }
    }
    return false;  // else return false to where this functionis being called
}

void print_winner(void)  // print winner of election
{
    int maxvote = 0;  // integer vairable in memory to store the value of the highest amount of votes that will be collected

    for (int i = 0; i < candidate_count; i++)  // loop through each of the candidates[]
    {
        if (candidates[i].votes >= maxvote)
        {
            maxvote = candidates[i].votes;
        }
    }
    for (int i = 0; i < candidate_count; i++)  // loop through each of the candidates[] (again)
    {
        if (candidates[i].votes == maxvote) // if the "ith" candaidates vote count == the maxvote variable
        {
            printf("%s WINNER: ", candidates[i].name);  // print the name of the candidate at this index
        }
    }
}