链表操作时巧用指针的指针

#include <stdio.h>
#include <stdlib.h>

struct node{
    int data;
    struct node *next;
} *head;

//sorted link-list
void insert(struct node *new_node){
    struct node *cur = head, *pre = NULL;
    while(cur != NULL && cur->data < new_node->data){
        pre = cur;
        cur = cur->next;
    }   

    new_node->next = cur;
    if(pre == NULL)
        head = new_node;
    else
        pre->next = new_node;
}

//use pointer to pointer can make things easier
void insert2(struct node *new_node){
    struct node **linkp = &head;
    while(*linkp !=NULL && (*linkp)->data < new_node->data){
        linkp = &(*linkp)->next;
    }

    new_node->next = *linkp;
    *linkp = new_node;
}

void show(){
    struct node *p = head;
    while(p){
        printf("%d , ", p->data);
        p = p->next;
    }
}


int main(){
    int i;
    struct node ns[] = {
        {80, NULL},
        {8, NULL},
        {1, NULL},
        {10, NULL},
    };
    for(i = 0; i < 4; i++){
        insert2(&ns[i]);
    }
    show();

    return 0;
}