Function which insert one Node in a List

[letthem]

Hi everybody,

I'm writing this post because I can't understand a function, which is thought to insert a node at the beginning of a linked list.

Here we have the function:

void pre_insert(struct list ** doubleptr, float value);

void pre_insert(struct list ** doubleptr, float value) { 
/*INPUT of the function:
-pointer which points to a pointer which points to a record;
-float.*/

struct list * temporary; /*I create a pointer to a record*/


    temporary = *doubleptr; /*The pointer I created point to the pointer
pointed by the doublepointer of the input*/


    *doubleptr = (struct list *)malloc(sizeof(struct list)); /*I create a new record, 
I give his adress to the double pointer of the input*/


    (*doubleptr)->value = value; /*I can't understand what happen here*/
    (*doubleptr)->next_ptr = temporary;/*I can't understand what happen here*/
    }

Can anyone tell me:
- if the sentences written as comments are correct;
- what happen in the last two lines.
Thank a lot!!!

[Salem]

Well you are going about it backwards.

Naming all your variables 'tmp' and 'ptr' doesn't add any clarity either.

void pre_insert(struct list **head, float value) { 
    struct list *newnode = malloc(sizeof(*newnode));
    newnode->value = value;
    newnode->next = *head;

    *head = newnode;
}