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the code is for creating a shop purchase, stock maintainence system
i have a problem in entering data from txt file to linked list with fscanf(fp,............) function;
the code below has the problems written in comments section but breifly, when i run the code in turbo c and enter the data at run time the contents go in the file correctly if i am not reading in older contents. every time i open the program the file is overridden.
when i read in the contents with fscanf() junk values start to get added in the file i dont know why. may be because i am using pointers instead of objects, but i do not know another way.
i know that my program is inefficient but still i want to know what is the problem with the code and how to resolve it
i have used many variables , some of them might never be used ,pls forgive me.
problem in the code will be found in the create function:
#include<alloc.h>
#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<graphics.h>
#define size 20
struct shop{
char name[size];
int quantity;
int price;
struct shop *next;
}*start;
typedef struct shop sh;
char u_name[30];
char u_pass[30];
int i,user,password;
int k=0,l=0;
char add_more;
char c,choice,c1,more;
void create()
{ FILE *fc,*fp;
struct shop *ptr,*temp,*g,*l,*m,*t,*i,*d;
char ch,v[20];
int r,z,w,flag=0;
//the code ***************from here******************
fc=fopen("storedata.txt","r");
d=(sh*)malloc (sizeof(sh));
d->next=NULL ;
i=d;
m=d;
while(fscanf(fc,"%s\t%d\t%d",m->name,m->quantity,m->price)!=EOF)
{
d=(sh*)malloc (sizeof(sh));
m->next=d;
m=m->next;
}
m->next=NULL;
fclose(fc);
t=i;
clrscr();
printf("NAME\t\t\tQUANTITY\t\t\t\tPRICE(RS)");
do
{
printf("\n%s ",t->name);
printf("\t\t\t%-20d",t->quantity);
printf("\t\t\t%-40d",t->price);
t=t->next;
}while(t!=NULL);
getch();
getch();
//*************till here********the smaller code part above is the code to read in the file which doesnt work correctly
start=i; // when i remove this line all the values entered in the file are correct but file is overridden every time i run it
ptr=start;
g=start;
l=start;
ch='y';
do
{
if(start!=NULL)
{
while(ptr->next!=NULL)
{
ptr=ptr->next;
}
printf("\nEnter the name of the item: ");
scanf("%s",&v);
printf("\nEnter the quantity of the item: ");
scanf("%d",&z);
printf("\nEnter the price of the item('0'if item present): ");
scanf("%d",&w);
while(g->next!=NULL)
{
if(strcmp(v,g->name)==0)
{
g->quantity=(g->quantity+z);
flag=1;
}
g=g->next;
}
if(g->next==NULL)
{
if(strcmp(v,g->name)==0)
{
g->quantity=(g->quantity+z);
flag=1;
} }
g=start;
if(flag==0)
{
temp=(sh*)malloc (sizeof(sh));
strcpy(temp->name,v);
temp->quantity=z;
temp->price=w;
ptr->next=temp;
ptr=ptr->next;
ptr->next=NULL;
}
printf("\nDo you want to add more nodes Y/N: ");
fflush(stdin);
scanf("%c",&ch);
flag=0;
}
else
if(start==NULL)
{
temp=(sh*) malloc (sizeof(sh));
printf("\nEnter the name of the item: ");
scanf("%s",&temp->name);
printf("\nEnter the quantity of the item: ");
scanf("%d",&temp->quantity);
printf("\nEnter the price of the item: ");
scanf("%d",&temp->price);
start=temp;
ptr=start;
g=start;
printf("\nDo you want to add more nodes Y/N: ");
fflush(stdin);
scanf("%c",&ch);
ptr->next=NULL;
}
}while(ch!='n');
fp=fopen("storedata.txt","w");
l=start;
while(l!=NULL)
{
fprintf(fp,"%s\t%d\t%d\n",l->name,l->quantity,l->price);
l=l->next;
}
fclose(fp);
}
void show()
{
FILE *fp;
int c;
clrscr();
fp=fopen("STOREDATA.TXT","r");
c=getc(fp);
while(c!=EOF)
{
putchar(c);
c=getc(fp);
}
fclose(fp);
}
int check(struct shop *m)
{
FILE *fp;
fp=fopen("storedata.txt","r");
while(fscanf(fp,"%s\t%d\t%d\n",m->name,m->quantity,m->price)!=EOF)
{
m=m->next;
}
fclose(fp);
return 0;
}
void delete()
{
FILE *fp;
char n[size],ch;
int k,j=0,i=0;
struct shop *temp,*l,*m,*f,*r,*a;
do
{
temp=start;
printf("\nEnter the item name you want to delete: ");
scanf("%s",&n);
printf("\nEnter the quantity: ");
scanf("%d",&k);
do
{
if(strcmp(n,temp->name)==0)
{
if(k==temp->quantity)
{
if(temp==start)
{
l=temp;
r=l;
l=l->next;
start=l;
free(r);
}
else
if(temp->next==NULL)
{
l=start;
for(i=1;i<j;i++)
{
l=l->next;
}
l->next=NULL;
free(temp);
}
else
{
l=start;
for(i=1;i<j;i++)
{
l=l->next;
}
f=temp->next;
l->next=f;
free(temp);
}
}
else
if(k!=temp->quantity)
{
temp->quantity=(temp->quantity-k);
printf("\nNow the number of items of %s are: %d",temp->name,temp->quantity);
}
break;
}
temp=temp->next;
j=j+1;
}while(temp!=NULL);
printf("\n\nDo you want to delete more items: ");
fflush(stdin);
scanf("%c",&ch);
}while(ch!='n');
fp=fopen("storedata.txt","w");
a=start;
while(a!=NULL)
{
fprintf(fp,"%s\t%d\t%d\n",a->name,a->quantity,a->price);
a=a->next;
}
fclose(fp);
}
void purchase()
{
FILE *fp;
char n[size],ch;
int k,j=0,i=0,s=0;
struct shop *temp,*l,*m,*f,*r,*a;
do
{
temp=start;
printf("\nEnter the item name you want to buy: ");
scanf("%s",&n);
printf("\nEnter the quantity: ");
scanf("%d",&k);
do
{
if(strcmp(n,temp->name)==0)
{
if(k==temp->quantity)
{
if(temp==start)
{
l=temp;
r=l;
l=l->next;
start=l;
free(r);
}
else
if(temp->next==NULL)
{
l=start;
for(i=1;i<j;i++)
{
l=l->next;
}
l->next=NULL;
free(temp);
}
else
{
l=start;
for(i=1;i<j;i++)
{
l=l->next;
}
f=temp->next;
l->next=f;
free(temp);
}
}
else
if(k!=temp->quantity)
{
temp->quantity=(temp->quantity-k);
}
break;
}
temp=temp->next;
j=j+1;
}while(temp!=NULL);
s=s+temp->price;
printf("\n\nDo you want to add more items:");
fflush(stdin);
scanf("%c",&ch);
}while(ch!='n');
printf("\n\nYour total bill is: %d",s);
fp=fopen("storedata.txt","w");
a=start;
while(a!=NULL)
{
fprintf(fp,"%s\t%d\t%d\n",a->name,a->quantity,a->price);
a=a->next;
}
fclose(fp);
}
void header()
{
clrscr();
printf("\n\t\t");
gotoxy(18,7);
printf("***********************************************");
gotoxy(18,8);
printf("\n\t\t");
gotoxy(18,9);
printf("* Goods Store *");
gotoxy(18,10);
printf("\n\t\t");
gotoxy(18,11);
printf("***********************************************");
gotoxy(25,18);
printf("Press Any Key To Continue........");
c1=getch();
}
void master_password()
{
printf("\n\n\n\n\n\n\t\t\t============================");
printf("\n\t\t\tEnter User Name:: ");
gets(u_name);
printf("\t\t\tEnter Password :: ");
gets(u_pass);
printf("\t\t\t============================");
printf("\n\t\t");
printf("Verifying...");
printf("\n\t\t");
for(i=0;i<47;i++)
{
delay(5);
cprintf("%c",987);
}
user=strcmp(u_name,"user");
password=strcmp(u_pass,"user");
if(user==0 && password==0)
{
clrscr();
printf("\n\t\t");
printf("Successfully Logged in");
main_menu();
}
else
{
clrscr();
printf("\n\t\t\t");
printf("Invalid Username or Password");
printf("\n\n\n\n\n\n\t\t\t");
printf("RE-");
master_password();
}
}
int main_menu()
{
do{
gotoxy(32,7) ;
printf("M A I N - M E N U");
gotoxy(32,10);
printf("1.Add to Stock");
gotoxy(32,12);
printf("2.Display Stock");
gotoxy(32,14);
cprintf("3.Delete from Stock");
gotoxy(32,16);
cprintf("4.Purchase");
gotoxy(32,18);
cprintf("5.EXIT");
gotoxy(32,21);
cprintf("Enter Your Choice: ");
choice=getche();
clrscr();
if(choice == 27)
break;
else if(choice=='1')
{
gotoxy(30,12);
create();
}
else if (choice=='2')
{
show();
getch();
clrscr();
main_menu();
}
else if(choice=='3')
{
delete();
}
else if(choice=='4')
{
purchase();
}
else if(choice=='5')
{
exit(0);
}
clrscr();
} while(choice!=4);
return 0;
}
void main()
{
check(start);
header();
master_password();
clrscr();
getch();
}
thanks
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