###### tags: `jserv課程筆記`

# Linux linked list note

根據 [你所不知道的 C 語言: linked list 和非連續記憶體](https://hackmd.io/@sysprog/c-linked-list?type=view)做的筆記

主要是把appendList裡面的程式碼從需要判斷是head或是next的pointer，改成像appendIndirect裡面的從存取這些pointer的位置去travel

---
## 程式碼

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

typedef struct List{
	int value;
	struct List *next; 
}list_entry;

void travelList(list_entry **head)
{
	list_entry **indirect = head;
	if(*indirect != NULL)
	{
		printf("[%x] = %d\n", *indirect, (*indirect)->value);
		travelList(&(*indirect)->next);
	}
}

void appendIndirect(list_entry **head, int value)
{
	 list_entry **indirect = head;
	 
	 while(*indirect != NULL)
	 {
	 	indirect = &(*indirect)->next;
	 }
	 
	 list_entry *node = new list_entry[1];
	 node->value = value;
	 node->next = NULL;
	 *indirect = node;
} 

void appendList(list_entry **head, int value)
{
	list_entry *pre = NULL;
	list_entry *cur = *head;
	
	list_entry *node = new list_entry[1];
	node->value = value;
	node->next = NULL;
	
	while(cur != NULL)
	{
		pre = cur;
		cur = cur->next;
	}
	
	if(pre == NULL)
		*head = node;
	else
		pre->next = node;
}

int main(void) {
    
    list_entry *head = NULL;
    appendList(&head, 0);
    appendList(&head, 1);
    appendList(&head, 2);
    
    appendIndirect(&head, 3);
    appendIndirect(&head, 4);
    appendIndirect(&head, 5);
    
    travelList(&head);
    
    system("pause");
    return 0;
}