Using insertion sort on a singly linked list

Question

So I have an assignment where I\'m giving a random list of number and I need to sort them using insertion sort. I must use a singly linked list. I looked around at other posts b

Answer 1

void linked_list::insertion_sort() {
    node * p = head;
    node * currentNode = head->next; // The node that is being compared at the moment.
    node * previousNode = head; // The node previous to the node being compared at the moment.
    //We can return from the sorting if the length of the linked list is less than 2.
    if (p == nullptr || p->next == nullptr) {
        return;
    }

    while (currentNode != nullptr) {
//If the current node is larger than or equal to the largest element of the sorted linked list on the left, we can move to the next element. 
//Helpful for an already sorted array.
        if(previousNode->value<=currentNode->value){
            currentNode = currentNode->next;
            previousNode = previousNode->next;
        }
        else{
//If the element is the smaller than the head element we need to take care of the head element.
            if (head->value > currentNode->value) {
                previousNode->next = currentNode->next;
                currentNode->next = head;
                head = currentNode;
            }else {
                p = head;
                while (p->next != NULL && p->next->value < currentNode->value) {
                        p = p->next;
                }
                previousNode->next = currentNode->next;
                currentNode->next = p->next;
                p->next = currentNode;
            }
        }
        currentNode = previousNode->next;
    }
}