CODEWITHSUNDEEP
clinked-list
oszust002
oszust002

Reputation: 65

Adding an element to end of the linked list

void    AddToEnd(double data ,int x, int y, element **list){
element *node, *tmp;
node=*list;
 if (data != 0)
 {
    tmp=malloc(sizeof(element));
    tmp->value=data;
    tmp->x_element=x;
    tmp->y_element=y;
    tmp->next=NULL;
    if (node !=NULL) {
        while (node->next != NULL) node=node->next;
        node->next=tmp;
    }
    else
    {
        *list=tmp;
    }
 }

}

How to get off this "if (node !=NULL)/else"? I want to add an element to the end of the list, but without this if/else which i used to adding first element.

Upvotes: 0

Views: 69

Answers (2)

M Oehm
M Oehm

Reputation: 29116

You can add one level of indirection and keep a pointer to the current node. Modify the list through this pointer. The initial value is the address of the head. After that, it holds the address of the next field of the previous node.

void AddToEnd(double data, int x, int y, element **list)
{
    if (data != 0) {
        element *tmp = malloc(sizeof(*tmp));

        tmp->value = data;
        tmp->x_element = x;
        tmp->y_element = y;        
        tmp->next = NULL;

        while (*list) {
            list = &(*list)->next;
        }

        *list = tmp;
    }
}

This code updates the list head when the list is empty.

Upvotes: 1

Thiyagu
Thiyagu

Reputation: 17880

You can create a dummy head node in main

element *list = malloc(sizeof(element));
list->value=0;
list->x_element=0;
list->y_element=0;
list->next=NULL;

And from here on you can use the AddToEnd modfied (without if/else) as

void AddToEnd(double data ,int x, int y, element **list){
element *node, *tmp;
node=*list;
 if (data != 0)
 {
    tmp=malloc(sizeof(element));
    tmp->value=data;
    tmp->x_element=x;
    tmp->y_element=y;
    tmp->next=NULL;

    while (node->next != NULL) node=node->next;
    node->next=tmp;

 }
}

So your list actually starts from second node in list

Upvotes: 1

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