Adt lab/linked lists - ประวัติรุ่นแก้ไข

Jittat: /* Copy-and-swap idiom */

2015-10-01T17:36:09Z

Copy-and-swap idiom

2015-10-01T17:34:06Z

Copy constructor and assignment operator

2015-10-01T17:03:37Z

Copy constructor and assignment operator

2015-10-01T17:00:57Z

Copy constructor

2015-10-01T16:57:19Z

Copy constructor

2015-10-01T16:56:10Z

Copy constructor

2015-10-01T16:53:46Z

Copy constructor

2015-10-01T15:59:00Z

Iterators

2015-10-01T15:58:39Z

Linked list class

2015-10-01T15:58:19Z

Linked list class

←รุ่นแก้ไขก่อนหน้า		รุ่นแก้ไขเมื่อ 17:36, 1 ตุลาคม 2558
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	=== Copy-and-swap idiom ===		=== Copy-and-swap idiom ===
		+
		+	Read at [http://stackoverflow.com/questions/3279543/what-is-the-copy-and-swap-idiom stackoverflow].
		+
		+	Here is a new version of the assignment operator using the copy-and-swap idiom.
		+
		+	<source lang="cpp">
		+	class LinkedList
		+	{
		+	// ...
		+	public:
		+	// ...
		+	LinkedList& operator=(LinkedList list);
		+
		+	void swap(LinkedList& l1, LinkedList& l2);
		+	};
		+	</source>
		+
		+	<source lang="cpp">
		+	void LinkedList::swap(LinkedList& l1, LinkedList& l2)
		+	{
		+	std::swap(l1.header, l2.header);
		+	std::swap(l1.tail, l2.tail);
		+	}
		+
		+	LinkedList& LinkedList::operator=(LinkedList list)
		+	{
		+	swap(*this, list);
		+	return *this;
		+	}
		+	</source>

	== Iterators ==		== Iterators ==

@@ แถว 127: / แถว 127: @@
 Another case when default copying operation does not work is when you use assignments, as in:
-<source>
+<source lang="cpp">
    LinkedList l1, l2;
@@ แถว 140: / แถว 140: @@
 The following shows the code for copy constructor and copy assignment operator for our LinkedList class.
 == Iterators ==

@@ แถว 123: / แถว 123: @@
 </source>
-But if you want l and l1 to be different lists, you need to implement its '''copy constructor''' yourself.  (Read more at [https://en.wikipedia.org/wiki/Copy_constructor_(C%2B%2B) copy constructor's article at wikipedia])
+But if you want l and l1 to be different lists, you need to implement its '''copy constructor''' yourself to handle object copy.  (Read more at [https://en.wikipedia.org/wiki/Copy_constructor_(C%2B%2B) copy constructor's article at wikipedia])
 == Iterators ==

@@ แถว 79: / แถว 79: @@
 </source>
-== Copy constructor ==
+== Copy constructor and assignment operator ==
 You can't pass an object of class <tt>LinkedList</tt> that we have written by value to other functions.  For example, if you write

@@ แถว 123: / แถว 123: @@
 </source>
-But if you want l and l1 to be different lists, you need to implement its '''copy constructor''' yourself.
+But if you want l and l1 to be different lists, you need to implement its '''copy constructor''' yourself.  (Read more at [https://en.wikipedia.org/wiki/Copy_constructor_(C%2B%2B) copy constructor's article at wikipedia])
 == Iterators ==

←รุ่นแก้ไขก่อนหน้า		รุ่นแก้ไขเมื่อ 16:56, 1 ตุลาคม 2558
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	This happens because the destructor has been called twice: once for <tt>l1</tt> and another for its copy <tt>l</tt> in function test. However, its copy, by default, was created by copying every data members of <tt>l1</tt>, i.e., its header and tail pointers point to the same location as of <tt>l1</tt>. When the list <tt>l</tt> was destroyed, its destructor also destroyed the original list data.		This happens because the destructor has been called twice: once for <tt>l1</tt> and another for its copy <tt>l</tt> in function test. However, its copy, by default, was created by copying every data members of <tt>l1</tt>, i.e., its header and tail pointers point to the same location as of <tt>l1</tt>. When the list <tt>l</tt> was destroyed, its destructor also destroyed the original list data.
		+
		+	To prevent this problem, you can pass <tt>l1</tt> by reference as in the next code. In this case l and l1 is the same list.
		+
		+	<source lang="cpp">
		+	void test(LinkedList& l)
		+	{
		+	l.append(1000);
		+	}
		+
		+	main()
		+	{
		+	LinkedList l1;
		+
		+	test(l1);
		+
		+	l1.append(10);
		+	}
		+	</source>
		+
		+	But if you want l and l1 to be different lists, you need to implement its '''copy constructor''' yourself.

	== Iterators ==		== Iterators ==

←รุ่นแก้ไขก่อนหน้า		รุ่นแก้ไขเมื่อ 16:53, 1 ตุลาคม 2558
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	== Copy constructor ==		== Copy constructor ==
		+
		+	You can't pass an object of class <tt>LinkedList</tt> that we have written by value to other functions. For example, if you write
		+
		+	<source lang="cpp">
		+	void test(LinkedList l)
		+	{
		+	l.append(1000);
		+	}
		+
		+	main()
		+	{
		+	LinkedList l1;
		+
		+	test(l1);
		+
		+	l1.append(10);
		+	}
		+	</source>
		+
		+	When you run your program, you may get this run-time error:
		+
		+	* Error in `./a.out': double free or corruption (fasttop): 0x0000000002138010 *
		+
		+	This happens because the destructor has been called twice: once for <tt>l1</tt> and another for its copy <tt>l</tt> in function test. However, its copy, by default, was created by copying every data members of <tt>l1</tt>, i.e., its header and tail pointers point to the same location as of <tt>l1</tt>. When the list <tt>l</tt> was destroyed, its destructor also destroyed the original list data.

	== Iterators ==		== Iterators ==

←รุ่นแก้ไขก่อนหน้า		รุ่นแก้ไขเมื่อ 15:58, 1 ตุลาคม 2558
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	== Linked list class ==		== Linked list class ==
		+	<source lang="cpp">
		+	typedef int valueType;
		+
		+	struct ListNode
		+	{
		+	valueType val;
		+	ListNode* next;
		+
		+	ListNode(valueType val, ListNode* next=0)
		+	: val(val), next(next) {}
		+	};
		+
		+	class LinkedList
		+	{
		+	private:
		+	ListNode* header;
		+	void free_list();
		+
		+	public:
		+	LinkedList();
		+	~LinkedList();
		+	void print_list();
		+	void insert_front(valueType x);
		+	};
		+
		+	LinkedList::LinkedList()
		+	{
		+	header = new ListNode(0);
		+	}
		+
		+	LinkedList::~LinkedList()
		+	{
		+	free_list();
		+	}
		+
		+	void LinkedList::print_list()
		+	{
		+	ListNode* node = header->next;
		+	while(node != 0) {
		+	cout << node->val << endl;
		+	node = node->next;
		+	}
		+	}
		+
		+	void LinkedList::insert_front(valueType x)
		+	{
		+	}
		+
		+	void LinkedList::free_list()
		+	{
		+	}
		+	</source>