I have some problem about add and delete node in linked list without malloc. I delete node then add node again and print list but nothing happen. T try to check add_node function and it work normally but I can not check with del_node. Here is my code:

#include <stdio.h>
#include <stdint.h>

#define MAX_NODES        20

typedef struct node
{
    uint8_t value;
    struct node *next;
}
node;

static node node_arr[MAX_NODES] = {[0 ... 19] = 0};
static uint8_t next_node = 0;

void Add_Node(node **head, uint8_t val, uint8_t index)
{
    node *new_node = &(node_arr[index]);  
    next_node  ;
    new_node->value = val;
    new_node->next = *head;    /* New node will point the current head*/
    *head = new_node;    /* Make new node become head of the list */
}

void Del_Node(node **head, uint8_t index)
{
    uint8_t run = 0;    /* Use run for reaching position */
    node *temp = *head;
    while((temp->next!= NULL) && (run != index)){
        temp = temp->next;
        run  ;
    }
    temp = temp->next;   /* Let current node become next node */
    next_node --;
}

int main(){
    node *head = NULL;
    Add_Node(&head, 2, 1);
    Add_Node(&head, 3, 2);
    Add_Node(&head, 4, 3);
    Add_Node(&head, 5, 4);
    Del_Node(&head, 3); // position 3 mean value 3 of list
    for (node *temp = head; temp != NULL; temp = temp->next)
    {
          printf(" %d ", temp->value);
    }
}

Thanks all.

CodePudding user response：

regarding your delete function: this code line doesnt do what i think you want it to do:

temp = temp->next;

youre trying to change local variable which is lost anyway when youre out of the function scope

try this fix: after you initialized temp add this line

node *prev = temp

in youre while loop the first line should be:

prev = temp;

and then outside the loop instead:

temp = temp->next;

put this line:

prev->next = temp->next;