이것은 연결된 목록에 대한 내 마지막 question 계속됩니다. 나는 그것에 대해 조금 더 연구했고, 구현해야 할 몇 가지 기능에 매달렸다. 내가 지금 질문하는 것은 destroy() 함수이다.C++ 연결된 목록 파괴 기능
모든 list_ item의 메모리를 해제해야합니다. 이 방법은 NULL이 발견 될 때까지 모든 list_item을 앞에서 끝까지 반복적으로 제거하는 것입니다. 그러나 어떤 이유로 그것은 단지 구조체에서 키 값을 삭제합니다. 여전히 노드가 있습니다.
다음 코드는 입니다. list_ destroy()에서 삭제 (my_ this)를 주석 처리 한 이유는 list_item이 삭제되도록 확인하는 것입니다. 당신의 destroy()
기능
#include <iostream>
using namespace std;
struct list_item
{
int key; // identifies the data
double value; // the data stored
struct list_item* next; // a pointer to the next data
};
// Why do you need this? And why would you want it anyway?
struct my_list
{
struct list_item* first; // a pointer to the first element of the list
};
//+-----------------------------------------------------
//| Module: list_init
//| Description: Initiate the list to an empty list
//| Input: A pointer to the uninitialized list
//| Result: The list is empty
//| Conditions: Assumes the list is uninitialized
//+-----------------------------------------------------
void list_init(struct my_list* my_this)
{
// ADD YOUR CODE HERE (approx 1 line)
//set the list NULL at beginning
my_this->first = NULL;
}
//+-----------------------------------------------------
//| Module: list_add
//| Description: Insert a new key, value pair in a sorted list
//| Input: The list to insert in and the key, value to insert
//| Result: The list is sorted according to keys and include the
//| new key, value pair
//| Conditions: The list is assumed to be sorted before the insert
//| Duplicate keys are allowed. The order of duplicate
//| keys is undefined
//+-----------------------------------------------------
void list_add(struct my_list* my_this, int key, double value)
{
// ADD YOUR CODE HERE (approx 23 lines)
//create new list_item node
list_item* new_node;
//allocate memory to it
new_node = new list_item;
//adding values
new_node->key = key;
new_node->value = value;
if (my_this->first != NULL)
{
new_node->next = my_this->first;
}
else
{
new_node->next = NULL;
}
my_this->first = new_node;
}
//+-----------------------------------------------------
//| Module: list_remove
//| Description: Remove the value with key from a sorted list
//| Input: The list to remove from and the key of the value to remove
//| Result: The list is sorted and do not contain a value with that key
//| Conditions: The list is assumed to be sorted before the insert
//| If duplicates of the key to remove exist only is removed.
//| It is undefined which of the duplicates that are removed.
//+-----------------------------------------------------
void list_remove(struct my_list* my_this, int key)
{
// ADD YOUR CODE HERE (approx 23 lines)
list_item *curr;
//allokera minne
curr = new list_item;
curr = my_this->first;
list_item *prev = new list_item;
for(int i=0; i<key;i++)
{
prev = curr;
curr = curr->next;
}
prev->next = curr->next;
delete(curr);
}
//+-----------------------------------------------------
//| Module: destroy
//| Description: First destroy any next list item, then release the
//| memory of the specified list item.
//| This will recursively destroy an list starting on this item.
//| Input: The list item to relese memory for (delete)
//| Result: The memory used by the list item, and any linked items,
//| are reclaimed by the OS
//| Further use of the list item is invalid
//| Conditions: The item is a pointer allocated with new and not
//| deleted before
//+-----------------------------------------------------
void destroy(struct list_item* item)
{
// ADD YOUR CODE HERE (approx 5 lines)
list_item *temp = new list_item;
if(item)
{
temp = item;
item = temp->next;
delete(temp);
destroy(item);
}
}
//+-----------------------------------------------------
//| Module: list_destroy
//| Description: Free the memory of an entire list.
//| Input: The list to destroy.
//| Result: All memory used by the list is reclaimed by the OS.
//| The list will become a valid but empty list.
//| Conditions: The list is initiated and valid.
//+-----------------------------------------------------
void list_destroy(struct my_list* my_this)
{
// ADD YOUR CODE HERE (approx 2 lines)
destroy(my_this->first);
// delete(my_this);
}
//+-----------------------------------------------------
//| Module: clone
//| Description: First create a new copy of the specified list
//| then append to the new item a clone of the next.
//| This will recursively create a copy of a entire
//| list starting on this item.
//| Input: The list item to clone.
//| Result: A copy of the specified item and any linked items.
//| Conditions: The item is valid.
//+-----------------------------------------------------
struct list_item* clone(struct list_item* item)
{
// ADD YOUR CODE HERE (approx 10 lines)
return item;
}
//+-----------------------------------------------------
//| Module: list_copy
//| Description: Copy an entire list
//| Input: The list to copy
//| Result: A new and valid list that are an independent copy
//| Conditions: The list is initiated and valid.
//+-----------------------------------------------------
struct my_list list_copy(struct my_list* my_this)
{
// ADD YOUR CODE HERE (approx 3 lines)
my_list *copy = new my_list;
copy = my_this;
return *copy;
}
struct my_iterator
{
struct list_item* current; // a pointer to the "current" list element
};
//+-----------------------------------------------------
//| Module: list_begin
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
struct my_iterator list_begin(struct my_list* my_this)
{
struct my_iterator i;
i.current = my_this->first;
return i;
}
//+-----------------------------------------------------
//| Module: iterator_end
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
bool iterator_end(struct my_iterator* i)
{
return i->current == NULL;
}
//+-----------------------------------------------------
//| Module: iterator_next
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
void iterator_next(struct my_iterator* i)
{
i->current = i->current->next;
}
//+-----------------------------------------------------
//| Module: iterator_get_key
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
int iterator_get_key(struct my_iterator* i)
{
return i->current->key;
}
//+-----------------------------------------------------
//| Module: iterator_get_value
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
double iterator_get_value(struct my_iterator* i)
{
return i->current->value;
}
//+-----------------------------------------------------
//| Module: main
//| Description:
//| Input:
//| Result:
//| Conditions:
//+-----------------------------------------------------
int main()
{
// ADD YOUR CODE HERE (approx 50 lines)
my_list*list = NULL;
list = new my_list;
list_init(list);
//list->first = NULL;
int key = 0;
double value = 0;
int i =0;
while(i <5)
{
++i;
cin>> value;
value = (int) value;
key = (int) value;
list_add(list,key,value);
cout << "Adding" << endl;
}
// my_list *list2 = new my_list;
// list_init(list2);
// list2 = list_copy(list);
//destroy the list and its content
list_destroy(list);
list_remove(list, 3);
cout << endl << "Print list" << endl;
for(my_iterator i = list_begin(list); !iterator_end(&i); iterator_next(&i))
{
cout << iterator_get_key(&i) << " " << iterator_get_value(&i) << endl;
}
list_destroy(list);
cout << endl << "Print list" << endl;
for(my_iterator i = list_begin(list); !iterator_end(&i); iterator_next(&i))
{
cout << iterator_get_key(&i) << " " << iterator_get_value(&i) << endl;
}
// list_destroy(list2);
return 0;
}
왜 std :: list를 사용하지 않으시겠습니까? 누군가 새로운 목록을 발명 할 때마다. –
나는 이것이 숙제라고 생각한다 - 그래서 포스터 힌트를주는 것이 그를 위해 일하거나 표준을 참조하는 것보다 더 도움이 될 것이다. : – hjhill
@Alexey : 나는 교육적인 목적으로 내기를했다. ... – Lucas