C ++ create/destroy/reverse/print a single-chain table

Note: The linked list created in this example contains the header node. for destruction, each node is destroyed, so it doesn't matter whether the linked list is

The printed linked list contains header nodes. That is to say, no data is printed at the head node. The experiment proves that the data at the head node is an abnormal value with a very large absolute value, that is, the random value without a value assignment.

For reverse configuration, no matter whether the initial linked list contains the header node or not, the reverse linked list does not contain the header node. the header node of the original linked list (if any) serves as the last node, it turns out that the last node is the first node and cannot be the header node, because this node has meaningful data. When printing the function in this example to output the reverse linked list data. For example, if the node value of the chain table containing the original header node is: 1 2 3 4 5, the print after the reverse setting is supposed to be 5 4 3 2 1, however, since the print function in this example is printed from the next node of the original node, the output is: 4 3 2 1-987453212, the last one is actually an unassigned memory space.

So be sure to include the header node !!!

# Include <iostream>

Using namespace STD;

 

Typedef struct _ Node

{

Int data;

Struct _ node * next;

} Node;

 

 

// Destroy the linked list

Bool destroy (node ** head)

{

Cout <"Destroy begin ----" <Endl;

If (null = * head)

{

Cerr <"link is null! "<Endl;

Cout <"Destroy over ----" <Endl;

Return false;

}

// Destroy the node from the beginning

While (* head! = NULL)

{

Node * q = (* head)-> next;

Free (* head );

* Head = Q;

}

* Head = NULL;

Head = NULL;

 

Cout <"Destroy over ----" <Endl;

Return true;

}

 

 

// Create a linked list

Node * Create ()

{

Node * head = NULL;

Node * P = NULL;

Node * s = NULL;

Head = (node *) malloc (sizeof (node); // create a header node. The data of the header node is not assigned a value.

If (null = head)

{

Cerr <"create error! "<Endl;

Return NULL;

}

 

P = head;

Int num = 0;

Cout <"Please intput :";

While (CIN> num)

{

If (num! = 0)

{

S = (node *) malloc (sizeof (node ));

If (null = s)

{

Destroy (& head); // if a new node fails to be allocated, the linked list is destroyed.

Return head;

}

Else

{

S-> DATA = num;

P-> next = s;

P = s;

}

}

Else

{

Break;

}

}

P-> next = NULL;

Return head;

}

 

// Print the linked list

Void print (node * head)

{

If (null = head)

{

Cerr <"head is null! "<Endl;

Return;

}

 

Node * P = head-> next; // print data from the first node to the next node.

Cout <"Print link :";

While (P! = NULL)

{

Cout <p-> data <"";

P = p-> next;

}

Cout <Endl;

}

 

// Reverse configuration of the linked list

Node * reverse (node * head)

{

Node * P1, * P2, * P3;

If (null = head | null = head-> next)

{

Cout <"link is null" <Endl;

Return head;

}

 

P1 = head;

P2 = p1-> next;

While (P2! = NULL)

{

P3 = P2-> next;

P2-> next = p1;

P1 = P2;

P2 = P3;

}

Head-> next = NULL;

Head = p1; // The head Pointer Points to the last node of the original linked list.

Return head;

}

 

 

Int main ()

{

Node * head = create ();

Cout

Print (head); // print the linked list

Node * head2 = reverse (head );

Print (head2 );

Destroy (& head2 );

Print (head2 );

 

Cout <Endl;

Return 0;

}