#include <stdio.h>
#include <stdlib.h>

struct Node
{
    int data;
    Node* next;
};

struct List
{
    Node* head;
    unsigned int length;
};

void addElemToList(List* list, unsigned int number)
{
    Node*temp;
    temp=(Node*)malloc(sizeof (Node));
    temp->next=NULL;
    temp->data=number;
    if(list->head == NULL)
    {
        list->head=temp;
    }else{
        temp->next=list->head;
        list->head=temp;
    }
    list->length++;
}

void delEleInList(List* list, unsigned int number)
{
    Node* current = list->head;
    if(number==1)
    {
        list->head=list->head->next;
        free(current);
    }else
    {
        for(unsigned int i=0;i<number-2;++i)
            current=current->next;
        Node*temp=current->next;
        current->next=temp->next;
        free(temp);
    }
    list->length--;
}


void reverse(List* list)
{
    Node* current = list->head;
    Node* prev= NULL, *next=NULL;
    while (current!=NULL)
    {
        next = current->next;
        current->next=prev;
        prev = current;
        current=next;
    }
    list->head=prev;
}

void print(List* list)
{
    Node*current=list->head;
    for(unsigned int i=0; i<list->length; ++i)
    {
        printf("%d ",current->data);
        current=current->next;
    }
}

int getItem(List* list, unsigned int index)
{

    Node* current=list->head;
    unsigned int count = 0;
    while(current != NULL)
    {
        if(count == index)
            return(current->data);
        count++;
        current = current->next;
    }
}


void setValueItem(List* list, unsigned int index, int newData)
{

    Node* current=list->head;
    unsigned int count = 0;
    while(current != NULL)
    {
        if(count == index)
            current->data=newData;
        count++;
        current = current->next;
    }
}


int main()
{
    List list;
    list.length=0;
    list.head=NULL;
    for(int i=1;i<=5;++i)
        addElemToList(&list,i);

    print(&list); printf("%s","\n");
    delEleInList(&list,4);
    print(&list); printf("%s","\n");
    int temp=getItem(&list,1);
    printf("\n%d\n\n",temp);
    reverse(&list);
    print(&list); printf("%s","\n");

    setValueItem(&list,2,123);
    print(&list); printf("%s","\n");

    return 0;
}