delete node linkedlist code example

Example: how to remove a node from a linked list in c

typedef struct node{
    int value; //this is the value the node stores
    struct node *next; //this is the node the current node points to. this is how the nodes link
}node;

node *rmvNode(node *head, int index){
    node *tmp = head;
    node *rmv;
    int count = 0;

    //base case for if the user enters a value greater then or equal to the length of the head
    //base case for if the user enters a value with a list of length 1. because in this library a list MUST contain one value minimum
    if(index >= len(head) || len(head) == 1){
        return NULL;
    }
  
    //if you want to remove the first value
    if(index == 0){
        rmv = head; //stores the head at this given moment in time
        head = tmp->next; //this jumps the position of the head making sure that the beginning is no longer part of the head
        free(rmv); //this frees the memory given to the initial head
        return head;
    }

    //if you want to remove index position 1
    if(index == 1){
        rmv = head->next;
        head->next = tmp->next->next;
        free(rmv);
        return head;
    }

    //if you want to remove the last value
    if(index == -1){
        
        while(count < len(head)-2){ //we do -2 because we want to access the node before the last one
            tmp = tmp->next;
            count += 1;
        }
        rmv = tmp->next;
        tmp->next = NULL;
        free(rmv);
        return head;
    }

    //remove anything else
    while(count < index-1){
        tmp = tmp->next;
        count += 1;
    }
    rmv = tmp->next;
    tmp->next = tmp->next->next;
    free(rmv);
    return head;

}