【CS50x】Plurality 题解

#include <cs50.h>
#include <stdio.h>
#include <string.h>
// 候选人的最大值
#define MAX 9
typedef struct
{
    string name;
    int votes;
} candidate;
candidate candidates[MAX];
int candidate_count;
bool vote(string name);
void print_winner(void);
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int main(int argc, string argv[])
{
    if (argc < 2)
    {
        printf("Usage: plurality [candidate ...]\n");
        return 1;
    }
    candidate_count = argc - 1;
    if (candidate_count > MAX)
    {
        printf("Maximum number of candidates is %i\n", MAX);
        return 2;
    }
    // 得到候选人数组
    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: ");
    // 检查所有人的投票结果
    for (int i = 0; i < voter_count; i++)
    {
        string name = get_string("Vote: ");
        if (!vote(name))
        {
            printf("Invalid vote.\n");
        }
    }
    // 展示赢家
    print_winner();
}
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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;
        }
    }
    return false;
}
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void print_winner(void)
{
    // TODO
    int max = 0;
    for (int i = 1; i < candidate_count; i++)
    {
        if (candidates[max].votes < candidates[i].votes)
        {
            max = i;
        }
    }
    for (int i = 0; i < candidate_count; i++)
    {
        if (candidates[max].votes == candidates[i].votes)
        {
            printf("%s\n", candidates[i].name);
        }
    }
    return;
}
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$ ./plurality Alice Bob
Number of voters: 3
Vote: Alice
Vote: Bob
Vote: Alice
Alice
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$ ./plurality Alice Bob
Number of voters: 3
Vote: Alice
Vote: Charlie
Invalid vote.
Vote: Alice
Alice
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$ ./plurality Alice Bob Charlie
Number of voters: 5
Vote: Alice
Vote: Charlie
Vote: Bob
Vote: Bob
Vote: Alice
Alice
Bob