单链表删除整表_单链表删除

单链表删除整表

Deletion can be at various positions like:

删除可以在各个位置进行，例如：

Deleting the first node
删除第一个节点
Deleting the last node
删除最后一个节点
Deleting the intermediate node
删除中间节点

删除单个链表中的第一个节点 (Deleting the first node in single linked list)

In such case, the head node is to be removed and the next node needs to be assigned as updated head node.

在这种情况下，将删除头节点，并且需要将下一个节点分配为更新的头节点。

Create a temporary node, say temp which points to the head node (first node) of the list.
创建一个临时节点，例如temp ，它指向列表的头节点(第一个节点)。
Move head node pointer to the immediate next node and delete (dispose) the temp node.
将头节点指针移动到紧邻的下一个节点，然后删除(布置)临时节点。

删除单个链接列表中的最后一个节点 (Deleting the last node in the single linked list)

In such case the last node is to be removed from list. The steps are following:

在这种情况下，最后一个节点将从列表中删除。步骤如下：

We need to keep track of the previous node of last node. That's why while traversing to the last node we need to set a prev node also which will point to the previous node of the tail node( last node) after traversal.
我们需要跟踪最后一个节点的前一个节点。这就是为什么在遍历到最后一个节点时，我们还需要设置一个prev节点，该节点将在遍历后指向尾节点(最后一个节点)的前一个节点。
So, we have two pointer, one tail node pointing to the last node and another is prev node pointing to the previous node of the last node.
因此，我们有两个指针，一个尾节点指向最后一个节点，另一个是上一个节点指向最后一个节点的前一个节点。
Set the next pointer of the prev node to NULL and delete the tail node. (last node)
将上一个节点为NULL的下一个指针，并删除尾节点。 (最后一个节点)

删除单个链接列表中的中间节点 (Deleting an intermediate node in the single linked list)

In such case an intermediate node is to be deleted. The approach is quite similar to the previous.

在这种情况下，中间节点将被删除。该方法与以前的方法非常相似。

Similar to the previous case, a curr node and a prev node is to be maintained. Curr node will point to the node to be deleted and prev node will point to the previous node.
与前一种情况类似，将保留curr节点和prev节点。 Curr节点将指向要删除的节点，而prev节点将指向上一个节点。
Set the next pointer of the prev node to the next pointer of curr node.
在上一个节点的next指针设置为CURR节点的下一个指针。
Delete the curr node.
删除curr节点。

链表中删除的C实现 (C implementation of deletion in a linked list)

#include <stdio.h>
#include <stdlib.h>
struct node{
int data; // data field
struct node *next;
};
void traverse(struct node* head){
struct node* current=head; // current node set to head
int count=0; // to count total no of nodes
printf("\n traversing the list\n");
while(current!=NULL){ //traverse until current node isn't NULL
count++; //increase node count
printf("%d ",current->data);
current=current->next; // go to next node
}
printf("\ntotal no of nodes : %d\n",count);
}
struct node* creatnode(int d){
struct node* temp=malloc(sizeof(struct node));
temp->data=d;
temp->next=NULL;
return temp;
}
int main(){
printf("creating the linked list by inserting new nodes at the begining\n");
printf("enter 0 to stop building the list, else enter any integer\n");
int k,count=1,x;
struct node* curr,*temp,*prev;
scanf("%d",&k);
struct node* head=creatnode(k); //buliding list, first node
scanf("%d",&k);
///inserting at begining//
while(k){
curr=creatnode(k);
curr->next=head;                     //inserting each new node at the begining
head=curr;
scanf("%d",&k);
}
traverse(head); // displaying the list
deleting the first node
printf("\ndeleting the first node.............\n");
temp=head;   // first node assigned to temp
head=head->next; // head node is updated
free(temp); // deleting the first node
traverse(head);  // displaying the list
printf("\nfirst node deleted...............\n");
/deleting the last node
printf("\ndeleting the last node.............\n");
temp=head->next;
prev=head;
while(temp->next!=NULL){
temp=temp->next;
prev=prev->next;
} 
// after traversal temp points to the last 
//node and prev to the previous node of the last node
prev->next=NULL;
free(temp);
traverse(head);
printf("\last node deleted................\n");
///deleting any intermediate node in the list
printf("\n enter the position of the node you want to delete\n");
scanf("%d",&x);
temp=head->next;
prev=head;
while(count!=x-1){
temp=temp->next;
prev=prev->next;
count++;
} // temp pointing to the node to be deleted and prev to the previous node 
prev->next=temp->next;
free(temp);
traverse(head);
return 0;
}

Output

输出量

creating the linked list by inserting new nodes at the begining      
enter 0 to stop building the list, else enter any integer 
1  
2  
3  
4  
5  
6  
7  
8  
9  
0  
traversing the list     
9 8 7 6 5 4 3 2 1        
total no of nodes : 9    
deleting the first node.............
traversing the list     
8 7 6 5 4 3 2 1          
total no of nodes : 8    
first node deleted...............   
deleting the last node............. 
traversing the list     
8 7 6 5 4 3 2 
total no of nodes : 7    
last node deleted................   
enter the position of the node you want to delete        
5  
traversing the list     
8 7 6 5 3 2   
total no of nodes : 6