Thread: file to arrays and search

Hi everyone!

i got problem in this function

Code:

void DisplayItemInfoForAParticularItem(){	FILE* f = fopen("items.txt", "r");
    int ItemID,ItemQuantity,PricePerUnit, i = 0;
    int ItemI[10], ItemQ[10],Price[10];
    printf("Enter itemID: ");
	scanf("%d",&ItemID);
    while( fscanf(f, "%d,", &ItemID) != EOF ) 
    {
        scanf("%d", &ItemI[i]);
		i++;
    }
    while( fscanf(f, "\t%d,", &ItemQuantity) != EOF ) 
    {
        scanf("%d", &ItemQ[i]);
		i++;
    }
     while( fscanf(f, "\t\t%d,", &PricePerUnit) != EOF ) 
    {
        scanf("%d", &Price[i]);
		i++;
    }
	
	if(ItemID != ItemQ[10])
	printf("Error");
	
    fclose(f);
   return ;
}

Where is the problem ... thanks


and this picture explain the function

You need a single loop, not three separate ones.

Keep things simple. Read a whole line from the file by using fgets, and parse it with sscanf.

If the item's ID is the one you want, display it. If not, move to the next.

If you have no more items to read and no items were displayed, output the error.

You don't need arrays at all here, just three variables for ID, Quantity and PricePerUnit.

fscanf does not work off of EOF it returns what it gets,

Code:

while ( fscanf (stream, "%d%d%d", stuff1,stuff2,stuff3) == 3 ) { do stuff }

why didn't you make a function to pass your file ( stream ) into your function .. it is not exactly you per se' , But I see that a lot, doing everything in the function.it's what I'd call bad program design, and wonder what they are teaching you and the others that pay money to get taught this. When it looks to be no program design is even being introduced into the classes the ones in here are taking.

anyways, just a quick short example

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


typedef struct MyStrutter
{
    char *N;
    int id;
}mystrutter;
 
int MyFunction1(FILE *f, char arrayA[])  
{
    int i = 0;
    char buffer;
  
    while ( (buffer = fgetc(f)) != EOF )
    {
        arrayA[i] = buffer;
        i++;
    }    
    return i;
}

void MyFunction2(mystrutter strut1[], FILE *f)   
{
    int i = 0;
     char name[30];
    memset(name, 0, sizeof(name));

    while ( fscanf (f, "%s%d",( strut1[i].N = strdup(name)), &strut1[i].id ) == 2) 
        i++;
}

int main (int argc, const char **argv)
{
    if ( argc < 2)
    {
        printf("no file yo %s\n", argv[1]);
        return -1;
    }
    //Open file once in main, then pass it
    //to functions to use it.
    FILE *fp;
    if ( (fp = fopen(argv[1], "r")) == NULL)
    {
        printf("FILE NULL\n");
        return -1;
    }
    int size = 0;
    char arr[100];
    mystrutter strutter1[3];
    
    memset(arr,0,sizeof(arr));
    memset(strutter1,0,sizeof(mystrutter));
    
    //returns amount of elements it 
    //actually used.
    size = MyFunction1(fp,arr);
    
    //use that same amount in the loop
    for ( int i = 0; i < size; i++)
        printf("%c",arr[i]);
    
    //reset stream
    fseek(fp,0,SEEK_SET);
    
    printf("\n");
    //use same stream in a different function
    MyFunction2(strutter1, fp);
     //is not an int so used size_t because of method of getting
     //size of array. 
    for ( size_t i = 0; i <  sizeof(strutter1)/sizeof(strutter1[0]); i++)
        printf("%s %d\n",strutter1[i].N, strutter1[i].id);
      
    
    fclose(fp);
return 0;
}
// file setup like this
(char) Name {where name is more than one letter}  (int) Id
bob 23
sally 55
Jill 292
// or this
bob
23
sally
55
Jill
292

Not that the function cannot be written the way you have it in here, and all of the other post I've seen others have the function open file and take in data. Because rule of thumb is functions are to do one thing. Mains function function is to deal with all of the other functions on top of what else it does.

Your assignment does not mention anything about putting your item.txt file into an array. It says to search for the ItemID in the text file. then if not found display an appropriate error message, otherwise the item information is displayed.

that requires a little more finesse then what you are doing.

verbatim,

"it then searches for this itemID in the items.txt text-file"

not read the text file into an array then search etc...

what does your actual data file look like , verbatim? Post it or upload it, if they gave you one to work with.