#import <Foundation/Foundation.h>

typedef struct Node_ {
    int value;
    struct Node_ *next;
    struct  Node_ *pre;
} Node;

Node *createNode(int value,Node *pre,Node *next) {
    Node* node = malloc(sizeof(Node));
    node->value = value;
   
    if (next!=NULL) {
        next->pre = node;
    }
    node->next = next;
   
    if (pre!=NULL) {
        pre->next = node;
    }
    node->pre = pre;
    return node;
}

void printList(Node *firstNode) {
    for (Node *node=firstNode; node!=NULL; node=node->next) {
        printf("%d\n",node->value);
    }
}

void rprintList(Node *end) {
    for (Node *node=end; node!=NULL; node=node->pre) {
        printf("%d\n",node->value);
    }
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Node *first = createNode(0, NULL,NULL);
        Node *end = first;
        
        end = createNode(1, end,NULL);
        end = createNode(2, end,NULL);
        end = createNode(3, end,NULL);
        end = createNode(4, end,NULL);
        end = createNode(5, end,NULL);
        end = createNode(6, end,NULL);
        end = createNode(7, end,NULL);
        end = createNode(8, end,NULL);
        end = createNode(9, end,NULL);
        
        
        printList(first);
        char *str = "reversed";
        printf("%s\n",str);
        rprintList(end);
        
    }
    return 0;
}