pvjc24/cv5/program.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
#define SIZE 100
#define MY_ERROR_OUTPUT stderr // chybovy vystup

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

// porovnavacia funkcia pre qsort
int compare_students(const void *a, const void *b) {
    const struct student *student_a = (const struct student *)a;
    const struct student *student_b = (const struct student *)b;
   
   // ak maju rovnaky pocet hlasov, porovnam podla abecedy
   if (student_a->votes != student_b->votes) {
	   return (student_b->votes - student_a->votes);
   }

	// inak porovnam podla poctu hlasov
	return strcmp(student_a->name, student_b->name);
}

int check_line(char *line, int *votes, char *name) {
   
   // najdenie prvej medzery v retazci
    char *space = strchr(line, ' ');
    
    // kontrola, ci sa nasla medzera
    if (space == NULL) {
        return 0; // neplatny riadok
    }
    
    //string na cislo premena
    char *end;
    *votes = strtol(line, &end, 10);
    if (*votes == 0) {
        return 0; // premena sa nepodarila
    }
	
    // nastavenie ukazovatela name na miesto za prvou medzerou
    char *name_start = space + 1;

    // nacitanie mena
    memset(name, 0, SIZE); // vynulovanie pomocneho pola pre meno
    int name_size = strlen(name_start) - 1; // velkost mena ale uz bez konca riadka
    if (name_size > 0) {
        memcpy(name, name_start, name_size);
    } else {
        return 0; // nepodarilo sa nacítat meno
    }

    return 1; 
}

// vyhladanie polozky v databaze
int find_student(struct student *students, int size, const char *name) {
    for (int i = 0; i < size; i++) {
        if (strcmp(students[i].name, name) == 0) {
            return i; // ak najde studenta
        }
    }
    return -1;
}

int main() {
    struct student databaza[SIZE];
    int size = 0;
    char line[SIZE];
    int votes; 
    char name[SIZE]; 
	bool chyba = false;

    // nacítanie a kontrola formatu vstupu
    while (1) {
		
        char* r = fgets(line,SIZE,stdin);
		if (r == NULL){
		printf("Nepodarilo nacitat nic\n");
		chyba = true;
		break;
		}
		
		if(line[0] == '\n'){
		break;
		}
		
		if (check_line(line, &votes, name) == 0) {
            printf("Neplatny format");
            continue; // preskoci riadok a nacita dalsi
        }

        // ci sa student nachadza v databaze
        int id = find_student(databaza, size, name);
        if (id < 0) {
            // Ak student nie je v databaze ta ho pridaj 
            if (size < SIZE) {
                strcpy(databaza[size].name, name);
                databaza[size].votes = votes;
                size++;
            } else {
                printf("Databaza je plna\n");
                break; // ked je databaza plna break
            }
        } else {
            // ak je v databaze aktualizuj pocet hlasov
            databaza[id].votes += votes;
        }
    }

    // triedim studentov
    qsort(databaza, size, sizeof(struct student), compare_students);
	
	if (chyba == false){
    printf("Vysledky:\n");
    for (int i = 0; i < size; i++) {
        printf("%d %s\n", databaza[i].votes, databaza[i].name);
    }
	}
    return 0;
}