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cmemory-managementfreedynamic-memory-allocation

How to free Adjency Linked List allocated memory?


I would like to free an Adjency Linked List memory Here is my data structs and two function which can allocate memory for the graph. How can I free the allocated memory ? Thanks for the help

struct ListPoint {
    int dest;
    int weight;
    struct ListPoint* next;
};
struct List {
    struct ListPoint* head;
};
struct Graf {
    int V;
    struct List* array;
};
struct ListPoint* newAdjencyListPoint(int dest, int weight)
{
    struct ListPoint* newPoint =
        (struct ListPoint*)malloc(sizeof(struct ListPoint));
    newPoint->dest = dest;
    newPoint->weight = weight; 
    newPoint->next = NULL;
    return newPoint;
}
struct Graf* createGraph(int V)
{
    struct Graf* graf = (struct Graf*)malloc(sizeof(struct Graf));
    graf->V = V;
    graf->array= (struct List*)malloc(V * sizeof(struct List));
    int i;
    for (i = 0; i < V; ++i)
        graf->array[i].head = NULL;
    return graf;
}

Solution

  • The following code will problaby be what you are looking for:

    freeLinkedList(struct List list){
       struct ListPoint *aux,*it = list.head;
       while(it != NULL){ //free a node and go to the next one
          aux = it->next;
          free(it);
          it = aux;
       }
    }
    freeAdjList(struct Graf* adj_list){
       for(int i=0;i<adj_list->V;i++) //free each linked list
          freeLinkedList(adj_list->array[i]);
       free(adj_list->array); //free the linked list array
       free(adj_list); //free the adj matrix itself
    }