Ниже приведен полный код для удаления последнего узла связанного простого списка, и, если он работает хорошо, функция void deleteLastNode ();
Но что конкретно означает эта часть? Мне кажется, что нужно сэкономить, потому что, когда цикл while закончен, у нас есть узел toDelete на последнем месте, а secondLastNode - как предпоследний
if(toDelete == head)
{
head = NULL;
}
. Этого достаточно:
void deleteLastNode()
{
struct node *toDelete, *secondLastNode;
if(head == NULL)
{
printf("List is already empty.");
}
else
{
toDelete = head;
secondLastNode = head;
/* Traverse to the last node of the list */
while(toDelete->next != NULL)
{
secondLastNode = toDelete;
toDelete = toDelete->next;
}
/* Disconnect link of second last node with last node */
secondLastNode->next = NULL;
/* Delete the last node */
free(toDelete);
printf("SUCCESSFULLY DELETED LAST NODE OF LIST\n");
}
}
Полный код такой: функция void deleteLastNode ();
/**
* C program to delete last node of Singly Linked List
*/
#include <stdio.h>
#include <stdlib.h>
/* Structure of a node */
struct node {
int data; // Data
struct node *next; // Address
}*head;
void createList(int n);
void deleteLastNode();
void displayList();
int main()
{
int n, choice;
/*
* Create a singly linked list of n nodes
*/
printf("Enter the total number of nodes: ");
scanf("%d", &n);
createList(n);
printf("\nData in the list \n");
displayList();
printf("\nPress 1 to delete last node: ");
scanf("%d", &choice);
/* Delete last node from list */
if(choice == 1)
deleteLastNode();
printf("\nData in the list \n");
displayList();
return 0;
}
/*
* Create a list of n nodes
*/
void createList(int n)
{
struct node *newNode, *temp;
int data, i;
head = (struct node *)malloc(sizeof(struct node));
/*
* If unable to allocate memory for head node
*/
if(head == NULL)
{
printf("Unable to allocate memory.");
}
else
{
/*
* Input data of node from the user
*/
printf("Enter the data of node 1: ");
scanf("%d", &data);
head->data = data; // Link the data field with data
head->next = NULL; // Link the address field to NULL
temp = head;
/*
* Create n nodes and adds to linked list
*/
for(i=2; i<=n; i++)
{
newNode = (struct node *)malloc(sizeof(struct node));
/* If memory is not allocated for newNode */
if(newNode == NULL)
{
printf("Unable to allocate memory.");
break;
}
else
{
printf("Enter the data of node %d: ", i);
scanf("%d", &data);
newNode->data = data; // Link the data field of newNode with data
newNode->next = NULL; // Link the address field of newNode with NULL
temp->next = newNode; // Link previous node i.e. temp to the newNode
temp = temp->next;
}
}
printf("SINGLY LINKED LIST CREATED SUCCESSFULLY\n");
}
}
/*
* Delete last node of the linked list
*/
void deleteLastNode()
{
struct node *toDelete, *secondLastNode;
if(head == NULL)
{
printf("List is already empty.");
}
else
{
toDelete = head;
secondLastNode = head;
/* Traverse to the last node of the list */
while(toDelete->next != NULL)
{
secondLastNode = toDelete;
toDelete = toDelete->next;
}
if(toDelete == head)
{
head = NULL;
}
else
{
/* Disconnect link of second last node with last node */
secondLastNode->next = NULL;
}
/* Delete the last node */
free(toDelete);
printf("SUCCESSFULLY DELETED LAST NODE OF LIST\n");
}
}
/*
* Display entire list
*/
void displayList()
{
struct node *temp;
/*
* If the list is empty i.e. head = NULL
*/
if(head == NULL)
{
printf("List is empty.");
}
else
{
temp = head;
while(temp != NULL)
{
printf("Data = %d\n", temp->data); // Print the data of current node
temp = temp->next; // Move to next node
}
}
}
В конце концов comprendГ, - Хорошие
void deleteLastNode()
{
struct node *toDelete, *secondLastNode;
if(head == NULL) //Si se cumple la LISTA ESTA VACIA
{
printf("List is already empty.");
}
else //SINO LA LISTA NO ESTA VACIA
{
toDelete = head;
secondLastNode = head;
/* Traverse to the last node of the list */
//COMIENZA EL BARRIDO DE NODOS DE CABEZA HASTA EL FINAL
while(toDelete->next != NULL)
{
secondLastNode = toDelete;
toDelete = toDelete->next;
}
//TERMINADO EL BUCLE SE HA OBTENIDO QUE *toDelete apunta al Ultimo
//Nodo y secondLastNode al Penultimo NODO y apunta al Ultimo
//Pero ese BUCLE WHILE NO AVANZARA NADA, SI LA LISTA Tiene UN SOLO
//NODO
//Y SI no aplica entonces aun toDelete==head y como hay un solo
//Nodo entonces, mando a cabeza=NULL que es lo mismo que aux=NULL
//DE ESA MAnera elimino el Unico NODO que habia
if(toDelete == head)
{
head = NULL;
}
else //si toDelete no es igual a headm entonces seguimos
//con el resultado del while
{
//tenemos a *anterior y *aux,
//mando a anterior->siguiente=NULL (para que sea el ultimo)
//libero a aux con free(aux) y lo desaparezco
/* Disconnect link of second last node with last node */
secondLastNode->next = NULL;
}
/* Delete the last node */
free(toDelete);
printf("SUCCESSFULLY DELETED LAST NODE OF LIST\n");
}
это - то, что я понял, спасибо за Ваше терпение