Having error in reading file C programming

Question

Figure 1 shows a text file (itemlist.txt) that store item code, item name, item price, and item quantity. Write a program to read the data from the text file and then display the item’s information which with 0 quantity on the screen.

Assume that data stored in the file are:

itemCode            a unique unsigned integer that differentiates an item from another
itemName            the name of an item (not more than 50 characters)
itemPrice           the current selling price of an item
itemQuantity        an integer that shows the quantity of an item

Also, assume that the fields in the file are separated by a comma.

File content:

 3123,Potato Chips,3.99,8
 2213,Peanut butter,7.99,0
 4533,Candy,1.05,14
 8744,Ice cream,2.50,0

Example output:

 Out-of-stock items:
 -------------------------------
 2213   Peanut butter   7.99
 8744   Ice cream   2.50

Can anyone read my code and see what is the problem? The program abnormally exits, but I don't know why..

#include <stdio.h>
#include <stdlib.h>
 int main()
 {
   unsigned int itemCode;
   char itemName[50];
   float itemPrice;
   int itemQuantity;

   FILE *fp;
   fp = fopen("itemlist.txt", "r");
   printf("%s","Out-of-stock items: \n");
   printf("-------------------------");

   while(!feof(fp)) {
    fscanf(fp, "%4u,%[^,],%f,%d", &itemCode, itemName, &itemPrice, &itemQuantity);

    if(itemQuantity == 0){
        printf("%u %s %f\n",itemCode,itemName,itemPrice);
    }


   }
    fclose(fp);

    return 0;



}

And also I would like to know that if the name of an item is not more than 50 characters, how many elements are there in the itemName array?

What is figure1 here please provide the diagram or delete that part? — Chinmaya B, Jul 17 '16 at 15:05
Use a debugger to identify where the problem is; that should go a good ways to identifying what the problem is, if not how to fix it. — Scott Hunter, Jul 17 '16 at 15:05
Perhaps checking the return value from `fscanf` would be a good starting point — Ed Heal, Jul 17 '16 at 15:06
http://stackoverflow.com/questions/5431941/why-is-while-feof-file-always-wrong — Mat, Jul 17 '16 at 15:07
[See use of feof is wrong in a while loop](http://stackoverflow.com/questions/5431941/why-is-while-feof-file-always-wrong) — Ed Heal, Jul 17 '16 at 15:10
I use the check fp != NULL . and the file could not be opened.. why is that so? i put the code n the text file in the same folder — Oliver Sim, Jul 17 '16 at 15:12
Omg, i named the text file as itemlist.txt not itemlist .. that seems to be the problem — Oliver Sim, Jul 17 '16 at 15:14
File does not exist where `fopen` is trying to find it. File permissions prevent it. It is locked by another process... — Ed Heal, Jul 17 '16 at 15:14
But the other issues (checking `fscanf` return value and read my link above) still exist — Ed Heal, Jul 17 '16 at 15:14

score 0 · Answer 1 · answered Jul 17 '16 at 17:39

Your main problem is probably not your program, but your environment. I have tested your program and it doesn't crash and it does make the correct output for the file in question. You should check your file permissions or make a new project with the program, then it can work.

score 0 · Answer 2 · answered Jul 17 '16 at 18:12

Your code causes undefined behavior if some input record contains itemName 50 or more characters length, because you are using limited buffer:

char itemName[50];

Maybe it would be better to implement custom parsing, due to scanf() is not flexible enough to meet all your possible inputs.

Having error in reading file C programming

2 Answers2