cmemorymallocdynamic-memory-allocationaccess-violation

C Access violation reading location 0xFFFFFFFFFFFFFFFF


I'm currently trying to test my code for adding a participant in a list, but I receive the error

Access violation reading location 0xFFFFFFFFFFFFFFFF.

when I try to free the memory.

participant.h

#pragma once

typedef struct {
    char *forename, *surname, *id;
    int *score;
}participant;

participant* create_part(char *id, char *forename, char *surname, int *score);

void destroy_part(participant* part);

participant.c

#include "participant.h"

participant* create_part(char *id, char* forename, char* surname, int *score) {
    /// Create a new participant
    /// : param forename : the participant's forename
    /// : param surname : the participant's surname
    /// : param score: the participant's scores
    /// : return: the participant

    participant* part = (participant*)malloc(sizeof(participant));
    part->id = malloc(sizeof(char) * 4);
    strcpy(part->id, id);
    part->forename = malloc(sizeof(char) * (strlen(forename) + 1));
    strcpy(part->forename, forename);
    part->surname = malloc(sizeof(char) * (strlen(surname) + 1));
    strcpy(part->surname, surname);

    part->score = malloc(sizeof(int) * 11);
    for (int i = 1; i <= 10; i++)
        part->score[i] = score[i];

    return part;
}

void destroy_part(participant* part) {
    /// Destroy a participant - free the memory
    /// :param part: the participant

    free(part->forename);
    free(part->surname);
    free(part->id);
    free(part->score);
    free(part);
}

repository.h

#pragma once
#include "participant.h"

typedef struct {
    participant** parts;
    int dim, capacity;
}repo;

repo* create_repo();

void destroy_repo(repo* part_lst);

repository.c

#include "repository.h"
#include "participant.h"

repo* create_repo() {
    // Create a list of participants
    // : return: the repo (list, dimension and capacity)

    repo* part_lst = (repo*)malloc(sizeof(repo));
    part_lst->dim = 0;
    part_lst->capacity = 100;
    part_lst->parts = (participant**)malloc(sizeof(participant*) * (part_lst->capacity));
    return part_lst;
}

void destroy_repo(repo* part_lst) {
    // Destroy the list of participants - free the memory
    // :param part_lst: the list of participants
    for (int i = 0; i < get_dim(part_lst); i++)
        destroy_part(get_participant(part_lst, i));
    free(part_lst->parts);
    free(part_lst);
}

int r_add_part(repo* part_lst, participant* part) {
    // Add a participant to the list
    // : param part_lst: the list of participants
    // : param part: the participant
    // : return: 1 - the participant was added, 0 - it wasn't

    if (get_dim(part_lst) < get_capacity(part_lst)) {
        (part_lst->parts)[part_lst->dim] = part;
        inc_dim(part_lst);
        return 1;
    }
    return 0;
}


void test_r_add_part() {
    // Test for function: r_add_part
    repo* l = create_repo();
    int sc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    participant *part1 = create_part("111", "Ana", "Popescu", sc);

    assert(r_add_part(l, part1) == 1);

    for (int i = 1; i < 3; i++)
        assert(r_add_part(l, part1) == 1);

    /// assert(r_add_part(l, part1) == 0);


    destroy_repo(l);
}

void test_r_add_part() {
    // Test for function: r_add_part
    repo* l = create_repo();
    int sc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    participant *part1 = create_part("111", "Ana", "Popescu", sc);

    assert(r_add_part(l, part1) == 1);

    for (int i = 1; i < 3; i++)
        assert(r_add_part(l, part1) == 1);

    /// assert(r_add_part(l, part1) == 0);


    destroy_repo(l);
}

enter image description here

The test I wanna run is in repository. I tried using the debugger but I still cannot figure it out.


Solution

  • You have added the same part several times in test_r_add_part.

    You then destroy all the entries in the repo.

    The second time you try to destroy the same part, that fails, because its already been destroyed

    You must create 3 parts like this

    participant *part1 = create_part("111", "Ana", "Popescu", sc);
    participant* part2 = create_part("222", "Joe", "Popescu", sc);
    participant* part3 = create_part("333", "Dave", "Popescu", sc);
    
    assert(r_add_part(l, part1) == 1);
    assert(r_add_part(l, part2) == 1);
    assert(r_add_part(l, part3) == 1);
    

    note that you are storing the scores in slots 1 to 10 rather tha 0 to 9. ie score[0] is not set