c - 段错误 11，C

Question

我一直在尝试用 C 语言实现一个 LinkedList 来实际实现我在 C 语言中学到的理论。我不断收到 Segmentation failure: 11. 任何帮助关于如何解决这个问题将受到高度赞赏。这是我的代码:

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

struct Element {
    int value;
    struct Element *nextElement;
};

struct LinkedList {
    struct Element *firstElement;   
};

void add(struct LinkedList *list, int value) {
    if(list->firstElement == NULL) {
        struct Element *newElement;
        newElement = malloc(sizeof(struct Element));

        newElement->value = value;

        list->firstElement = newElement;
    } else {
        struct Element *lastElement;

        lastElement = list->firstElement;

        while(lastElement->nextElement != NULL) {
            lastElement = lastElement->nextElement;   
        }

        struct Element *newElement;
        newElement = malloc(sizeof(struct Element));

        newElement->value = value;

        lastElement->nextElement = newElement;
    }
}

void showAllElements(struct LinkedList *list) {
    struct Element *lastElement = list->firstElement;

    while(lastElement != NULL) {
        printf("%d\n", lastElement->value);
        lastElement = lastElement->nextElement;
    }
}

int main()
{
    struct LinkedList list;
    add(&list, 5);
    add(&list, 10);
    add(&list, 15);
    showAllElements(&list);

    return 0;   
}

Answer 1

那么，您的代码存在一些问题。未分配struct LinkedList list。当你执行 list->firstElement 时，它会出错。初始化它

struct LinkedList list = {NULL}

此外，newElement 不会分配nextElement。您还需要将其设置为NULL，否则访问时会出错。

    struct Element *newElement;
    newElement = malloc(sizeof(struct Element));

    newElement->value = value;
    newElement->nextElement = NULL;