更新链接列表中的项目(Update an Item in Linked List)
实现 (Implementation)
该算法的实现如下 -
#include <stdio.h>
#include <stdlib.h>
struct node {
int data;
struct node *next;
};
struct node *head = NULL;
struct node *current = NULL;
struct node *prev = NULL;
//insert link at the first location
void insert(int data) {
// Allocate memory for new node;
struct node *link = (struct node*) malloc(sizeof(struct node));
link->data = data;
link->next = NULL;
// If head is empty, create new list
if(head==NULL) {
head = link;
head->next = link;
return;
}
current = head;
// move to the end of the list
while(current->next != head)
current = current->next;
// Insert link at the end of the list
current->next = link;
// Link the last node back to head
link->next = head;
}
void remove_data(int data) {
int pos = 0;
if(head==NULL) {
printf("Linked List not initialized");
return;
}
if(head->data == data) {
if(head->next != head) {
current = head;
while(current->next!=head) {
current = current->next;
}
current->next = head->next;
head = head->next;
return;
} else {
head = NULL;
printf("List is empty\n");
exit(0);
}
} else if(head->data != data && head->next == NULL) {
printf("%d not found in the list\n", data);
return;
}
current = head;
while(current->next != head && current->data != data) {
prev = current;
current = current->next;
}
if(current->data == data) {
prev->next = prev->next->next;
free(current);
} else
printf("%d not found in the list.", data);
}
//display the list
void printList() {
struct node *ptr = head;
printf("\n[head] =>");
//start from the beginning
while(ptr->next != head) {
printf(" %d =>",ptr->data);
ptr = ptr->next;
}
printf(" %d =>",ptr->data);
printf(" [head]\n");
}
int main() {
insert(10);
insert(20);
insert(30);
insert(1);
insert(40);
insert(56);
printf("Original List -");
printList();
remove_data(1);
printf("List after removal -");
printList();
return 0;
}
输出 (Output)
该方案的产出应该是 -
Original List -
[head] => 10 => 20 => 30 => 1 => 40 => 56 => [head]
List after removal -
[head] => 10 => 20 => 30 => 40 => 56 => [head]
