为什么我的代码会跳过某些节点？

Question

我写这段代码来存储学生的数据记录＆＃39;名字，姓氏，分数和邮政编码。我几乎已经完成了所有工作但是我的Print（）函数没有打印节点2的第一个元素（第二个学生的名字），当我输入2个以上的节点时，它变成了一个无限循环，我做错了什么？

#include <stdio.h>
#include <string.h>
#include<stdlib.h>
void Insert(char first[20], char last[20], float data, char zip[50]);
void delete(int e);
void Print();
double median();
struct node
{
    char first_name[20];
    char last_name[20];
    float score;
    char zip_code[50];
    struct node *ptr;
};
int n;
struct node* head =NULL;
struct node* tail=NULL ;
void Insert(char first[20], char last[20], float data, char zip[50])
{

    struct node *temp=(struct node*)malloc(sizeof(struct node));
temp->ptr=NULL;
    strcpy(temp->first_name,first);
    strcpy(temp->last_name,last);
    temp->score=data;
    strcpy(temp->zip_code,zip);

    if(head==NULL)
    {
        head=temp;
        tail=temp;
        return;
    }
    tail->ptr=temp;
    tail=temp;
    free(temp);
    temp=NULL;

}
void delete(int e)
{
    int i;
    struct node *temp=(struct node*)malloc(sizeof(struct node));
    temp=head;
    if(e==1)
    {
        head=temp->ptr;
        free(temp);
        return;
    }
    else if(e==n)
    {
        while(temp->ptr->ptr!=NULL)
        {
            temp=temp->ptr;
        }
        temp->ptr=NULL;
        free(temp->ptr);
        return;
    }
    for(i=0; i<(e-2); ++i)
        temp=temp->ptr;
    struct node *temp1=temp->ptr;
    temp->ptr=temp1->ptr;
    free(temp1);
}
void Print()
{
    struct node *temp=(struct node*)malloc(sizeof(struct node));
    temp=head;
    printf("Data entered is below: \n");
    while(temp!=NULL)
    {

        printf("First Name: %s, Last Name: %s, Score: %.2f, Zip Code: %s",temp->first_name,temp->last_name,temp->score,temp->zip_code);
        temp=temp->ptr;
        printf("\n");
    }
    printf("\n\n\n");
}
double median()
{
    double median,tmp;;
    double *ex=(double*)malloc(sizeof(double));/*head*/
    double *exe=(double*)malloc(sizeof(double));/*dynamic*/
    ex=exe;
    int i=1,term,j;
    struct node *temp=(struct node*)malloc(sizeof(struct node));
    temp=head;
    while(i<=n)
    {
        temp->ptr;
        *exe=temp->score;

        exe++;
    }
    for(i=0; i<n; i++)
    {
        for(j=i+1; j<n; j++)
        {
            if( *(ex+i) > *(ex+j))
            {
                tmp = *(ex+i);
                *(ex+i) = *(ex+j);
                *(ex+j) = tmp;
            }
        }
    }
    if(n%2==0)
    {
        /*even;median=n/2-1*/

        term=(n/2)-1;
        median= (*(ex+(term-1)));
        return median;
    }
    /*odd; median=n-1/2*/
    term=(n-1)/2;
    median= (*(ex+(term-1)));

    return median;
}
int main()
{
    char name1[20],name2[20], code[50];
    float x;
    int i,option,index;
    printf("Enter the number of nodes: ");
    scanf("%d",&n);
    printf("Please enter the records of students in the following format(click enter for new students)\n");
    printf("First_Name Last_Name Score Zip_Code\n");
    for(i=1; i<=n; ++i)
    {

        scanf(" %s",name1);
        scanf(" %s",name2);
        scanf(" %f",&x);
        scanf(" %s",code);
        Insert(name1,name2,x,code);

    }
    printf("\n");
    while(1)
    {
        printf("Choose one of the following options: \n");
        printf("Print records (press 1)\nAdd a new record (press 2)\nDelete record(s) (press 3)\nSearch by zip code (press 4)\nSearch by score range (press 5)\nFind median score (press 6)\nExit the program (press 0)\n");
        scanf("%d",&option);
        switch(option)
        {
        case 0:
        {
            /*Exit Program*/
            exit(0);
            break;
        }
        case 1:
        {
            /*print*/
            Print();
            break;
        }
        case 2:
        {
            /*insert*/
            getchar();
            printf("Enter the new record in the following format: \nFirst_Name Last_Name Score Zip_Code\n");
            scanf("%s",name1);
            scanf("%s",name2);
            scanf("%f",&x);
            scanf("%s",code);
            getchar();
            Insert(name1,name2,x,code);

            break;
        }
        case 3:
        {
            /*delete*/
            printf("Enter the node/record to be deleted: ");
            scanf("%d",&index);
            delete(index);
            printf("The deletion of record %d has been succesfully completed!\n\n",index);
            break;
        }
        case 4:
        {
            /*search by zip*/

            break;
        }
        case 5:
        {
            /*search by score*/

            break;
        }
        case 6:
        {
            /*find median*/
            printf("Median score for the entered records is: %f",median());
            break;
        }

        }/*switch*/
    }/*while*/
    return 0;

}

Answer 1

Insert函数持有对已释放数据的引用：

tail=temp;
free(temp);

在tail被释放后尝试使用const stream = require('stream'); const readable = new stream.Readable({read(){}}); readable.on('data', () => console.log('data')); process.nextTick(() => console.log('next tick')); readable.push('foo'); readable.push('foo'); 引用的存储是一个错误。