c - C 中插入时指针未修改

Question

优先级队列的程序，我对指针有疑问，我将头传递给插入，但它在插入中没有修改，如你所见，我正在打印头

• 在插入和主要
• 在插入中打印一些非零的内容
• 在 head 中它为零

    #include<stdio.h>
    #include<stdlib.h>
    struct node{
        int data;
        int priority;
        struct node* next;
    };
    struct node* getnewnode(int data,int priority){
        struct node* newnode=malloc(sizeof(struct node));
        newnode->data=data;
        newnode->next=NULL;
        newnode->priority=priority;
        return newnode;
    }
    void insert(struct node* head,int data,int priority){

        struct node* newnode=getnewnode(data,priority);
        if(head==NULL){
            head=newnode;
            printf("head in insert is %d",head);
            return;
        }

        if(head->priority > newnode->priority){
            newnode->next=head;
            head=newnode;
            return;
        }
        if(head->priority <= newnode->priority ){
            struct node* temp=head;
            while(temp->priority <= newnode->priority ){
                temp=temp->next;
            }
            newnode->next=temp->next;
            temp->next=newnode;
            return;
        }
    }
    int removee(struct node* head){
        if(head==NULL)
            return -1;
        int temp=head->data;
        head=head->next;
        return temp;
    }
    int main(){
        struct node* head=NULL;
        insert(head,3,5);
        printf("\n head in main is %d",head);

    }

Answer 1

没有任何 if() 语句的 super 简化版本:

<小时/>

void insert(struct node **head, int data, int priority){

    struct node *newnode = getnewnode(data, priority);

    for( ; *head && (*head)->priority <= newnode->priority; head = &(*head)->next)
        {;}

    newnode->next = *head;
    *head = newnode;

    return;

}

<小时/>

...如果您不喜欢空循环，您可以添加 if(...) break;:

<小时/>

void insert(struct node **head, int data, int priority){

    struct node *newnode = getnewnode(data, priority);

    for( ; *head ; head = &(*head)->next) {
        if( (*head)->priority > newnode->priority) break;
        }

    newnode->next = *head;
    *head = newnode;

    return;

}