碰到了不会做的C语言链表问题

Question

代码如下：

#include<cstring>
#include<stdio.h>
#include<stdlib.h>
#define n 2
    struct book                        //建立结构体数组
    {
     char zhanghao[8];
    char num[11];
    char suoyinhao[6];
    char time[10];
    char returntime[10];
    }a[n],b[n],c[n];


    struct node                         //建立结构体链表
 {
    char zhanghao[8];
    char num[11];
    char suoyinhao[6];
    char time[10];
    char returntime[10];
    struct node *next;
   };
    FILE *fp1,*fp2,*fp3;
    struct node *insertone(struct node *head1)  /*输入a.txt中所有的信息，并构建新的带头结点的链表*/
     {
        int i;
      struct node *p,*q;
      head1=q=(struct node *)malloc(sizeof(struct node));
     printf("         ~~~~~~欢迎进入借还书信息系统，请输入相关信息~~~~~~\n");
      for(i=0;i<n;i++)
    {
     p=(struct node *)malloc(sizeof(struct node));
    printf("账号：");
    scanf("%s",a[i].zhanghao);
    printf("学号：");
    scanf("%s",a[i].num);
    printf("图书索引号：");
    scanf("%s",a[i].suoyinhao);
    printf("借书时间：");
    scanf("%s",a[i].time);
    printf("\n");
      q->next=p;
      q=p;
     }
      p->next=0;
      return head1;
     }

      struct node *inserttwo(struct node *head2)  /*输入b.txt中所有的信息，并构建新的带头结点的链表*/
     {
        int i;
      struct node *p,*q;
      head2=q=(struct node *)malloc(sizeof(struct node));
      for(i=0;i<n;i++)
    {
          p=(struct node *)malloc(sizeof(struct node));
    printf("账号：");
    scanf("%s",b[i].zhanghao);
    printf("学号：");
    scanf("%s",b[i].num);
    printf("图书索引号：");
    scanf("%s",b[i].suoyinhao);
    printf("还书时间：");
    scanf("%s",b[i].returntime);
    printf("\n");
      q->next=p;
      q=p;
     }
      p->next=0;
      return head2;
     }


      void showone(struct node *head1)    /*保存到a.txt文件中并显示出来*/
     { 
         int i;
       struct node *temp;
      temp=head1;
       printf("a.txt\n");
    fp1=fopen("a.txt","w");
    for(i=0;i<n;i++)
    if(fwrite(&a[i],sizeof(struct book),1,fp1)!=1)          /*将结构体数组a[i]中的数据写入a.txt文件*/
    printf("文件写入数据错误\n");
    fclose(fp1);
    fp1=fopen("a.txt","r");
    printf("\n账号      学号      图书索引号    借书时间\n");         
    for(i=0;i<n;i++)
    {
    fread(&a[i],sizeof(struct book),1,fp1);                                          /*从a.txt文件中读出数据并打印出来*/
    printf("%s %11s %8s %15s\n",a[i].zhanghao,a[i].num,a[i].suoyinhao,a[i].time);
    temp=temp->next;
    }
    fclose(fp1);
     }
   
 void showtwo(struct node *head2)   /*保存到b.txt文件中并显示出来*/
 {
         int i;
       struct node *temp;
      temp=head2;
    printf("b.txt\n");
    fp2=fopen("b.txt","w");
    for(i=0;i<n;i++)
    if(fwrite(&b[i],sizeof(struct book),1,fp2)!=1)                /*将结构体数组b[i]中的数据写入b.txt文件*/
    printf("文件写入数据错误\n");
    fclose(fp2);
    fp2=fopen("b.txt","r");
    printf("\n账号      学号      图书索引号    还书时间\n");
    for(i=0;i<n;i++)
    {
    fread(&b[i],sizeof(struct book),1,fp2);                                                /*从a.txt文件中读出数据并打印出来*/
    printf("%s %11s %8s %15s\n",b[i].zhanghao,b[i].num,b[i].suoyinhao,b[i].returntime);
    temp=temp->next;
    }
    fclose(fp2);
 }

  struct node *loadone(void)  /*将文件a中的数据生成一个链表，如果文件不存在，则是一个空链*/
   {
       int i;
    struct node *head1, *p,*q;
    struct book a[n];
    head1=(struct node *)malloc(sizeof(struct node));
    q=head1=NULL;
 if((fp1=fopen("a.txt","rb"))==NULL)
    return head1;
 else
 {while(!feof(fp1))
    {
      for(i=0;i<n;i++)
        if(fread(&a[i],sizeof(struct book),1,fp1)==1)
        {p=(struct node *)malloc(sizeof(struct node));
          strcpy(p->zhanghao,a[i].zhanghao);
          strcpy(p->num,a[i].num);    
          strcpy(p->suoyinhao,a[i].suoyinhao);
          strcpy(p->time,a[i].time);
          head1=p;
          p->next=q;
          q=head1;
        }
    }
    fclose(fp1);
    return head1;
 }
   }

     
     struct node *loadtwo(void)  /*将文件b中的数据生成一个链表，如果文件不存在，则是一个空链*/
   {
       int i;
    struct node *head2, *p,*q;
    struct book b[n];
    head2=(struct node *)malloc(sizeof(struct node));
    q=head2=NULL;
 if((fp2=fopen("b.txt","rb"))==NULL)
    return head2;
 else
 {while(!feof(fp2))
    {
      for(i=0;i<n;i++)
        if(fread(&b[i],sizeof(struct book),1,fp2)==1)
        {p=(struct node *)malloc(sizeof(struct node));
          strcpy(p->zhanghao,b[i].zhanghao);
          strcpy(p->num,b[i].num);    
          strcpy(p->suoyinhao,b[i].suoyinhao);
          strcpy(p->returntime,b[i].returntime);
          head2=p;
          p->next=q;
          q=head2;
        }
    }
    fclose(fp2);
    return head2;
 }
   }
    void  hebing(struct node *head1, struct node *head2)   /*合并两个文件*/
    {
        char ch;
        FILE *fp1,*fp2,*fp3;
        if((fp1=fopen("a.txt","r"))==NULL)
        {printf("打开文件a.txt失败!\n");
         exit(1);
        }
        else
         printf("打开文件a.txt成功!\n");
       if((fp2=fopen("b.txt","r"))==NULL)
       {printf("打开文件b.txt失败!\n");
        exit(2);
       }
        else
        printf("打开文件b.txt成功!\n");
       if((fp3=fopen("c.txt","r"))==NULL)
       {printf("打开文件c.txt失败!\n");
      exit(3);
       }
      else
     printf("打开文件c.txt成功!\n");
while((ch=fgetc(fp1))!=EOF)
        fputc(ch,fp3);
       while((ch=fgetc(fp2))!=EOF)
      fputc(ch,fp3);
       fclose(fp1);
       fclose(fp2);
       fclose(fp3);
    }

     struct node *loadthree(void)  /*将文件c中的数据生成一个链表，如果文件不存在，则是一个空链*/
   {
       int i;
    struct node *head, *p,*q;
    struct book c[n];
    head=(struct node *)malloc(sizeof(struct node));
    q=head=NULL;
 if((fp3=fopen("c.txt[]","rb"))==NULL)
    return head;
 else
 {while(!feof(fp3))
    {
      for(i=0;i<n;i++)
        if(fread(&c[i],sizeof(struct book),1,fp3)==1)
        {p=(struct node *)malloc(sizeof(struct node));
          strcpy(c[i].zhanghao,p->zhanghao);
          strcpy(c[i].num,p->num);    
          strcpy(c[i].suoyinhao,p->suoyinhao);
           strcpy(c[i].time,p->time);
          strcpy(c[i].returntime,p->returntime);
          head=p;
          p->next=q;
          q=head;
        }
    }
    fclose(fp3);
    return head;
 }
   }
     void showthree(struct node *head)    /*保存c.txt文件中的信息并显示出来*/
     { 
         int i;
       struct node *p;
       p=head;
       printf("c.txt\n");
    fp3=fopen("c.txt","w");
    for(i=0;i<n;i++)
    if(fwrite(&c[i],sizeof(struct book),1,fp3)!=1)
    printf("文件写入数据错误\n");
    fclose(fp3);
    fp3=fopen("c.txt","r");
    printf("\n账号      学号      图书索引号    借书时间      还书时间\n");
    for(i=0;i<n;i++)
    {
    fread(&c[i],sizeof(struct book),1,fp3);
    printf("%s %11s %8s %15s %15s\n",c[i].zhanghao,c[i].num,c[i].suoyinhao,c[i].time,c[i].returntime);
    p=p->next;
    }
    fclose(fp3);
     }

  main()
   {
     struct node *head;
      struct node *head1;
       struct node *head2;
      head1=insertone(head1);    //输入a.txt文件中的信息
    head2=inserttwo(head2);      //输入b.txt文件中的信息
     showone(head1);             //保存a.txt文件中的信息并打印出来
     showtwo(head2);             //保存b.txt文件中的信息并打印出来
    head1=loadone();             //从a.txt中读取相关信息存储到链表中
    head2=loadtwo();             //从b.txt中读取相关信息存储到链表中
    hebing(head1,head2);          //合并两个文件
    head=loadthree();            //对合并后的文件建立链表
     showthree(head);            //保存链表中的信息到文件中并打印出来
   }

a文件和b文件合并后的c文件内容一直不显示呢？

Answer 1

void showthree(struct node *head1, struct node *head2)
{
    int i;
    struct node *temp1, *temp2;
    temp1 = head1;
    temp2 = head2;

    // Open "c.txt" for writing
    fp3 = fopen("c.txt", "w");
    if (fp3 == NULL)
    {
        printf("Error opening file c.txt!\n");
        exit(1);
    }

    // Combine information from "a.txt" and "b.txt" and save to "c.txt"
    while (temp1 != NULL && temp2 != NULL)
    {
        if (strcmp(temp1->suoyinhao, temp2->suoyinhao) < 0)
        {
            // Save information from "a.txt" to "c.txt"
            if (fwrite(temp1, sizeof(struct node), 1, fp3) != 1)
            {
                printf("Error writing to file c.txt!\n");
                exit(1);
            }
            temp1 = temp1->next;
        }
        else if (strcmp(temp1->suoyinhao, temp2->suoyinhao) > 0)
        {
            // Save information from "b.txt" to "c.txt"
            if (fwrite(temp2, sizeof(struct node), 1, fp3) != 1)
            {
                printf("Error writing to file c.txt!\n");
                exit(1);
            }
            temp2 = temp2->next;
        }
        else
        {
            // Save combined information from "a.txt" and "b.txt" to "c.txt"
            strcpy(temp1->returntime, temp2->returntime);
            if (fwrite(temp1, sizeof(struct node), 1, fp3) != 1)
            {
                printf("Error writing to file c.txt!\n");
                exit(1);
            }
            temp1 = temp1->next;
            temp2 = temp2->next;
        }
    }

    // Save remaining information from "a.txt" or "b.txt" to "c.txt"
    while (temp1 != NULL)
    {
        if (fwrite(temp1, sizeof(struct node), 1, fp3) != 1)
        {
            printf("Error writing to file c.txt!\n");
            exit(1);
        }
        temp1 = temp1->next;
    }
    while (temp2 != NULL)
    {
        if (fwrite(temp2, sizeof(struct node), 1, fp3) != 1)
        {
            printf("Error writing to file c.txt!\n");
            exit(1);
        }
        temp2 = temp2->next;
    }

    // Close "c.txt"
    fclose(fp3);

    // Open "c.txt" for reading
    fp3 = fopen("c.txt", "r");
    if (fp3 == NULL)
    {
        printf("Error opening file c.txt!\n");
        exit(1);
    }

    // Display information from "c.txt" on screen
    printf("c.txt\n");
    while (fread(&c[i], sizeof(struct book), 1, fp3) == 1)
    {
        printf("账号：%s ", c[i].zhanghao);
        printf("学号：%s ", c[i].num);
        printf("图书索引号：%s ", c[i].suoyinhao);
        printf("借书时间：%s ", c[i].time);
        printf("还书时间：%s\n", c[i].returntime);
        i++;
    }

    // Close "c.txt"
    fclose(fp3);
}

head1 = insertone(head1);
head2 = inserttwo(head2);
showthree(head1, head2);