CS50 Problem Set 3 (Fall 2019) - Plurality

Plurality.c

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

// Max number of candidates
#define MAX 9

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

// Array of candidates
candidate candidates[MAX];

// Number of candidates
int candidate_count;

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

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

    // Populate array of candidates
    candidate_count = argc - 1;
    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: ");

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

        // Check for invalid vote
        if (!vote(name))
        {
            printf("Invalid vote.\n");
        }
    }

    // Display winner of election
    print_winner();
}

// Update vote totals given a new vote
bool vote(string name)
{
    // TODO
    for (int i = 0; i < candidate_count; i++)
    {
        if (strcmp(candidates[i].name, name) == 0)
        {
            candidates[i].votes++;
            return true;
        }
    }
    // TODO end
    return false;
}

// Print the winner (or winners) of the election
void print_winner(void)
{
    // TODO
    int maxvotes = 0;
    // find highest number of votes
    for (int i = 0; i < candidate_count; i++)
    {
        if (candidates[i].votes > maxvotes)
        {
            maxvotes = candidates[i].votes;
        }
    }
    // print winners
    for (int i = 0; i < candidate_count; i++)
    {
        if (candidates[i].votes == maxvotes)
        {
            printf("%s\n", candidates[i].name);
        }
    }

    // TODO end
    return;
}

Can someone please explain how the "vote(name)" function is called in the 'main' code? I only see one condition "if (!vote(i, j, name))" related to this function, and as I understand this just prints "Invalid vote" if the "vote" returns false.

Sorry to bother you. I am doing my problem set 3 make plurality. I am really confused on the print_winner function definition part // find the highest number of votes.
Could you explain it a little bit when you have time please?
Appreciate it.
I think the theory behind the print_winner function goes as follows;
1)Set an initial maxvotes value to 0 as a starting point to compare to
2)Iterate over the list of candidates, updating the maxvotes value as you move through each element of the array
3)Iterate over the list of candidates again printing those that have numbers of votes equal to the maxvotes values as you go
I am currently working through this myself and I think that is the logic behind it
Thank you very much. Now I understand how the "int maxvotes" works. You are so smart!!
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