pvjc24/cv5/program.c

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

#define SIZE 100

struct student {
    char name[SIZE];
    int votes;
};

// comparison function for sorting students
int compare(const void *a, const void *b) {
    struct student *student_a = (struct student *) a;
    struct student *student_b = (struct student *) b;

    if (student_a->votes > student_b->votes) {
        return -1;
    } else if (student_a->votes < student_b->votes) {
        return 1;
    } else {
        // if the votes are the same, compare names
        return strcmp(student_a->name, student_b->name);
    }
}

int main() {
    struct student students[SIZE];
    int size = 0;

    // read student data from standard input
    while (1) {
        char line[SIZE];
        memset(line, 0, SIZE);
        char *r = fgets(line, SIZE, stdin);

        // check if the line is empty or just contains newline character
        if (r == NULL || (r[0] == '\n' && strlen(r) == 1)) {
            // end of input
            break;
        }

        // check if the line was truncated
        if (strlen(line) == SIZE - 1 && line[SIZE - 2] != '\n') {
            // line was truncated, handle the error
            fprintf(stderr, "Error: input line is too long\n");
            return 1;
        }

        // parse the string and extract number of votes and student name
        int votes;
        char name[SIZE];
        if (sscanf(line, "%d %[^\n]", &votes, name) != 2) {
            // error, input was not in expected format
            // print error message and exit
            fprintf(stderr, "Error: invalid input format\n");
            return 1;
        }

        // check if this student already exists
        int found = 0;
        for (int i = 0; i < size; i++) {
            if (strcmp(students[i].name, name) == 0) {
                // add votes to existing student
                students[i].votes += votes;
                found = 1;
                break;
            }
        }

        // if the student was not found, add a new student
        if (!found) {
            strcpy(students[size].name, name);
            students[size].votes = votes;
            size++;
        }
    }

    // sort students based on their votes
    qsort(students, size, sizeof(struct student), compare);

    // print the results
    printf("Vysledky:\n");
    for (int i = 0; i < size; i++) {
        printf("%d %s\n", students[i].votes, students[i].name);
    }

    return 0;
}