Picture此程序必须执行菜单选项。首先，它以必须保存用户数据文件的功能开始，但是在执行代码后会发生错误。如何更改程序，使其首先将数据写入文件，然后再读取。 searchbyfamname和searchbybooks应该寻找书籍和家庭的读者。是否存在写入错误，如果是，该如何更改代码？
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct catalogue
{
char code [8];
char name [80];
char address [80];
char famname [20];
char fathname [20];
char EGN [10];
int numbooks;
struct catalogue*next;
};
struct catalogue* head=NULL;
struct catalogue*current=NULL;
void start();
void reg();
void searchbybooks();
void searchbyfamname();
void del();
void ShowAll();
void End();
int main()
{
char code [8],name [80],address[80],famname[20],fathname[20],EGN [10];
int j,m,n,k,i,e;
int flag=-1;
FILE *fp;
fp=fopen ("catalogue.txt","wb");
printf ("Enter the new ID:\n");
scanf("%s",code);
j=strlen (code);
j++;
printf ("Enter the new name:\n");
scanf ("%s",name);
m=strlen(name);m++;
printf ("Enter a new father name:\n");
scanf ("%s",fathname);
i=strlen(fathname);i++;
printf ("Enter a new family name:\n");
scanf("%s",famname);
k=strlen(famname);k++;
printf ("Enter the new address:\n");
scanf ("%s",address);
n=strlen (address);n++;
printf ("Enter the new EGN:\n");
scanf ("%s",EGN);
e=strlen (EGN);e++;
fwrite(&j,sizeof(int),1,fp);
fwrite(code,j,1,fp);
fwrite(&m,sizeof(int),1,fp);
fwrite(name,m,1,fp);
fwrite(&k,sizeof(int),1,fp);
fwrite(famname,k,1,fp);
fwrite(&i,sizeof(int),1,fp);
fwrite(fathname,i,1,fp);
fwrite(&n,sizeof(int),1,fp);
fwrite(address,n,1,fp);
fwrite(&e,sizeof(int),1,fp);
fwrite(EGN,e,1,fp);
fwrite(&flag,sizeof(int),1,fp);
fclose(fp);
int choice=0;
for (;;)
{
printf ("----------------MENU----------------\n");
printf ("0.Show everything saved in the file.\n");
printf ("1.Register new reader.\n");
printf ("2.Search readers with most books.\n");
printf ("3.Search reader by family name.\n");
printf ("4.Delete a reader by code number only if no books are
taken.\n");
printf ("5.Exit.\n");
do {
printf ("Enter your choice:\n");
scanf ("%d",&choice);
fflush (stdin);
}
while(!(choice>=0 && choice<=5));
printf("%d\n",choice);
switch(choice)
{
case 0:
{
start();
ShowAll();
head=NULL;
break;
}
case 1:
{
start();
reg();
End();
head=NULL;
break;
}
case 2:
{ start();
searchbybooks();
head=NULL;
break;
}
case 3:
{ start();
searchbyfamname();
head=NULL;
break;
}
case 4:
{ start();
del();
End ();
head=NULL;
break;
}
case 5:
{
exit(5);
}
}
}
return 0;
}
void start ()
{
FILE *fp;
int i;
int flag;
if (fp=fopen("catalogue","rb")==NULL)
{
printf ("Error opening file for reading.\n");
exit (1);
}
while(1){
if(fread(&flag, sizeof(int), 1, fp)!=1)
{
printf("Error reading!");
exit(4);
}
if (flag==-1)
break;
struct catalogue*temp=(struct catalogue*)malloc(sizeof(struct
catalogue));
if(head==NULL)
{
head=temp ;
current=head;
current->next=NULL;
}
else
{
current->next=temp;
current=temp;
current->next=NULL;
}
if((fread(temp->code,flag,1,fp))!=1){
printf("Error!");
exit (20);
}
if((fread(temp->name,flag,1,fp))!=1){
printf("Error!");
exit (20);
}
if((fread(temp->address,flag,1,fp))!=1){
printf("Error!");
exit (20);
}
if((fread(temp->EGN,flag,1,fp))!=1){
printf("Error!");
exit (21);
}
if((fread(&temp->numbooks,sizeof(int),1,fp)!=1)){
printf("Error!");
exit(23);
}
}
fclose(fp);
}
void reg ()
{
struct catalogue *temp;
temp=head;
while(temp->next!=NULL)
{
temp=temp->next;
}
struct catalogue *newcat;
newcat=(struct catalogue*) malloc(sizeof(struct catalogue));
printf("Enter the new ID:\n ");
scanf("%s",newcat->code);
printf("Enter the new name:\n ");
scanf("%s",&newcat->name);
printf("Enter the new father name:\n ");
scanf("%s",&newcat->fathname);
printf("Enter the new family name:\n ");
scanf("%s",&newcat->famname);
printf("Enter the new address:\n ");
scanf("%s",&newcat->address);
printf("Enter the new EGN:\n ");
scanf("%s",&newcat->EGN);
newcat->next=NULL;
temp->next=newcat;
printf("Add new client:SUCCESSFUL!\n");
}
void searchbybooks()
{
char *arr;
int flag=0;
arr=(char*)malloc(20);
printf("Input client taken books: \n \n");
gets(arr);
struct catalogue*temp;
temp=(struct catalogue*)malloc(sizeof(struct catalogue));
temp=head;
while(temp!=NULL)
{
if(!(strcmp(temp->numbooks,arr))){
printf("\t %d \n \n",temp->numbooks);
flag=1;
break;
}
temp=temp->next;
}
if(flag==0) {
printf("Can't find client with %d taken books! \n \n",arr);
}
}
void searchbyfamname()
{
char *arr;
int flag=0;
arr=(char*)malloc(20);
printf("Input client family name: %s \n \n");
gets(arr);
struct catalogue*temp;
temp=(struct catalogue*)malloc(sizeof(struct catalogue));
temp=head;
while(temp!=NULL)
{
if(!(strcmp(temp->famname,arr))){
printf("\t %s \n \n",temp->famname);
flag=1;
break;
}
temp=temp->next;
}
if(flag==0) {
printf("Can't find client with %s family name. - %s \n \n",arr);
}
}
void del()
{
struct catalogue* prev_item=head;
struct catalogue* curr_item=head;
int f=0;
char *arr;
arr=(char*)malloc(20);
printf("Input client ID: \n");
gets(arr);
while(curr_item!=NULL)
{
if(strcmp (curr_item->code, arr) == 0)
{
if(curr_item == head)
{
head = head->next;
prev_item = head;
f=1;
}
else
prev_item->next = curr_item->next;
free(curr_item);
curr_item = prev_item;
}
prev_item = curr_item;
if(f == 0)
curr_item=curr_item->next;
f=0;
}
}
void ShowAll()
{
struct catalogue*m;
for(m=head; m!=NULL; m=m->next)
{
printf("ID: %s name: %s %s %s address: %s EGN: %s \n \n", m-
>code, m->name,m->fathname,m->famname , m->address, m->EGN);
}
}
void End ()
{
FILE *fp;
int flag=-1;
if((fp=fopen("catalogue","wb"))==NULL){
printf("Error opening file!");
exit(0);
}
struct catalogue *temp;
temp=head;
int j,k,m,i,n,e;
while(temp!=NULL){
j=strlen(temp->code);j++;
if(fwrite(&j,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(temp->code,j,1,fp)!=1){
printf("Error!");
exit(1);
}
k=strlen(temp->name);k++;
if(fwrite(&k,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(temp->name,k,1,fp)!=1){
printf("Error!");
exit(1);
}
i=strlen(temp->fathname);i++;
if(fwrite(&i,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(temp->fathname,i,1,fp)!=1){
printf("Error!");
exit(1);
}
n=strlen(temp->famname);n++;
if(fwrite(&n,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(temp->famname,n,1,fp)!=1){
printf("Error!");
exit(1);
}
m=strlen(temp->address);m++;
if(fwrite(&m,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(temp->address,m,1,fp)!=1){
printf("Error!");
exit(1);
}
e=strlen(temp->EGN);e++;
if(fwrite(&e,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
if(fwrite(temp->EGN,e,1,fp)!=1){
printf("Error!");
exit(1);
}
if(fwrite(&temp->numbooks,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
temp=temp->next;
}
if(fwrite(&flag,sizeof(int),1,fp)!=1){
printf("Error!");
exit(1);
}
fclose(fp);
}
return 0;
}