Hash Table: it doesn't save correctly [closed] - c

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What my program do..
read a text file of format
store name 1
itemcode quantity
itemcode quantity
.
.
store name 2
itemcode quantity
itemcode quantity
.
.
When you Run my code you will Ask to Enter a task.
there are three options
L itemcode quantity
entering the above sequence will print all the stores which contains that item with the given quantity.
U itemcode quantity storename
this option takes three arguments itemcode int quantity and storename
the Function for this option just update the given store with the amount quantity.
Q
this option call my Savefile method which save the current data structure back to the file.
Problem.
There is a problem I am facing.
whenever I update file it updates successfully but when Enter Command Q to quit and save it doesn't save correctly..
save_file(char *)
it lost whole data just the first store is save..
stores.txt
carrefour_Milan
12345678 12
23456766 16
carrefour_Torino
12345678 65
67676765 12
Carrefour_Vercelli
23456766 20
and also can you help me in finding the time complexity of
int listfile(char *)
and
int updatefile(char *,int ,char *)
I mean Big O.
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAX_ITEM 1000
#define MAXS 129
#define MAXL 132
#define MAXC 9
FILE *fp;
typedef struct store{
char Storename[MAXS];
int quantity;
struct store *NEXT;
}STORE;
typedef struct item{
char item_code[MAXC];
struct store *Stores;
struct item *NEXT;
}ITEM;
ITEM *list_item[MAX_ITEM];
int readfile(char *fname);
int update_file(char *item_code,int qty,char *name);
int hash(char *item_code);
int save_file(char *fname);
void init();
void init(){
int i;
for( i=0;i<MAX_ITEM;i++)
list_item[i]=NULL;
}
int readfile(char *fname){
char *p,line[MAXL+1],storen[MAXL+1];
int pos;
ITEM *current=NULL,*prev=NULL;
STORE *s_cur=NULL,*s_prev=NULL;
char itemcode[MAXC];int qty;
if((fp=fopen(fname,"r"))==NULL)
return -1;
while(!feof(fp)){
if(fgets(line,MAXL+1,fp)==NULL)
break;
if((p=strchr(line,'\n'))==NULL)
;
else
*p='\0';
if(line[0]>='a' && line[0]<='z' ||line[0]>='A' && line[0]<='Z')
strcpy(storen,line);
else{
//fgets(line,MAXL,fp);
if(sscanf(line,"%s %d",itemcode,&qty)>0){
current=(ITEM *)malloc(sizeof(ITEM));
if(current==NULL)
return -1;
pos=hash(itemcode);
if(list_item[pos]==NULL){
list_item[pos]=current;
if((s_cur=(STORE *)malloc(sizeof(STORE)))==NULL)
return -1;
strcpy(s_cur->Storename,storen);
strcpy(current->item_code,itemcode);
s_cur->quantity=qty;
current->Stores=s_cur;
s_cur->NEXT=NULL;
current->NEXT=NULL;
}
else{
ITEM *q=list_item[pos];
if((s_cur=(STORE *)malloc(sizeof(STORE)))==NULL)
return -1;
while(q!=NULL){
if(strcmp(q->item_code,itemcode)==0){
STORE *temp=q->Stores,*temp_a=NULL;
if(temp==NULL){
q->Stores=s_cur;
strcpy(s_cur->Storename,storen);
s_cur->quantity=qty;
s_cur->NEXT=NULL;
}
else{
while(temp!=NULL){
temp_a=temp;
temp=temp->NEXT;
}
temp_a->NEXT=s_cur;
strcpy(s_cur->Storename,storen);
s_cur->quantity=qty;
s_cur->NEXT=NULL;
}
}
q=q->NEXT;
}
if(q==NULL){
q=current;
current->NEXT=NULL;
current->Stores=s_cur;
strcpy(s_cur->Storename,storen);
s_cur->quantity=qty;
s_cur->NEXT=NULL;
}
}
}
}
}
fclose(fp);
return 0;
}
int listfile(char *item_code,int qty){
int i;
ITEM *u=NULL;
item_code[strlen(item_code)]='\0';
if(list_item[hash(item_code)]==NULL)
return -1;
else{
u=list_item[hash(item_code)];
while(u!=NULL){
if(strcmp(u->item_code,item_code)==0){
STORE *temp=u->Stores;
while(temp!=NULL){
if(temp->quantity>=qty){
printf("STORE %s\n",temp->Storename);
}
temp=temp->NEXT;
}
}
u=u->NEXT;
}
}
return 0;
}
int update_file(char *item_code,int qty,char *name){
ITEM *u=NULL;
item_code[strlen(item_code)]='\0';
name[strlen(name)]='\0';
if(list_item[hash(item_code)]==NULL)
return -1;
u=list_item[hash(item_code)];
if(u==NULL)
return -1;
while(u!=NULL){
if(strcmp(u->item_code,item_code)==0){
STORE *temp=u->Stores;
while(temp!=NULL){
if(strcmp(temp->Storename,name)==0)
temp->quantity+=qty;
temp=temp->NEXT;
}
}
u=u->NEXT;
}
return 0;
}
int hash(char *item_code){
int sum=0,s=0;
while(item_code[s]!='\0'){
sum+=33*item_code[s];
s++;}
return sum%MAX_ITEM;
}
void clear(){
char c;
while(c!='\n')
scanf("%c",&c);
}
main(){
int y;
char fname[]="stores.txt",line[MAXL],command,z[MAXS];
char x[MAXC];
init();
if(readfile(fname)==-1)
printf("Error reading file!");
else{
do{
printf("Enter task:");
fgets(line,MAXL,stdin);
sscanf(line,"%c",&command);
switch(command){
case 'L': sscanf(line,"%c%s%d",&command,x,&y);
if(listfile(x,y)==-1)
printf("No items were found\n");
break;
case 'U':sscanf(line,"%c%s%d%s",&command,x,&y,z);
if(update_file(x,y,z)==0)
printf("Update OK\n");
else
printf("Error when updating\n");
break;
case 'Q':if(save_file(fname)==0)
printf("Done\n!");
break;
default:printf("Enter correct command\n");
break;
}
}while(command!='Q');
}
}
int save_file(char *fname){
ITEM *p=NULL,*q=NULL;
int num=0,i,j;
char str[MAXS];
if((fp=fopen(fname,"w"))==NULL)
return -1;
for( i=0;i<MAX_ITEM;i++){
if(list_item[i]==NULL)
;
else{
p=list_item[i];
while(p!=NULL){
STORE *s=p->Stores;
if(s==NULL)
;
else{
if(strcmp(s->Storename,"0000\0")!=0){
strcpy(str,s->Storename);
// puts(str);
fprintf(fp,"%s\n",str);
}
while(s!=NULL){
for( j=0;j<MAX_ITEM;j++){
if(list_item[j]==NULL)
;
else{
q=list_item[j];
while(q!=NULL){
STORE *st=q->Stores;
if(st==NULL)
;
else{
while(st!=NULL){
if(strcmp(st->Storename,str)==0 && strcmp(st->Storename,"0000\0")!=0){
printf("%s %d\n",q->item_code,st->quantity);
fprintf(fp,"%s %d\n",q->item_code,st->quantity);
strcpy(st->Storename,"0000\0");
}
st=st->NEXT;
}
}
q=q->NEXT;
}
}
}
s=s->NEXT;
}
}
p=p->NEXT;
}
}
}
fclose(fp);
return 0;
}

Answer 1

This is an inconsistent and unreadable mess. I suggest as first steps to refactor the layout.
Repair the indentation so it reflects the code structure. Chose a bracing style and use it consistently. Something like this
if(x){
;
}else{
foo();
}
should better look like this:
if (x) {
;
}
else {
foo();
}
That's a much better starting point for any debugging and maintenance. And there is a lot of maintenance necessary.

Answer 2

Your code is very inefficient. For example when reading the file, you malloc the store structure separately in both branches of the if statement, and copy the store name in three different places, again in all different code paths. Why not simply malloc the store structure and initialise it correctly before you work out where to put it?
Also in the read file function, if the hash table position corresponding to the item is not empty, the memory allocated to "current" gets leaked.
Furthermore, if you actually find a match for the item, you don't break out of the loop which means that the block of code beginning:
if(q==NULL){
q=current;
gets executed.
Lastly (for now), if a slot in the hash table is filled but there is no matching itemcode then the item won't get put into the hash table. Look at your code. At what point do you assign "current" to any part of the chain that starts at "list_item[pos]"? You don't. Doing "q = current" just stores one value in another variable. What you need is something like:
current->next = list_item[pos];
list_item[pos] = current;
To add it on at the beginning of the list.
I suggest you fix your file reading function before worrying about your file writing function.
P.s. an upvote and a request for more comments may get you some more help. Depending on how busy I am and whether others can also be bothered to help.