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code fix

Posted on 2000-03-08
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Last Modified: 2010-04-15
help..
somethings wrong w/ this code..
esp on mallocing.

#define MAX 20

typedef struct indexrecord {
   int    index[26];
   long   start;
   long   count;
} indexrecord;

indexrecord *idxrec[MAX];
long wordctr=0;

void readindex(void) {
   FILE *fpidx;
   register int i, j;
   int intvar;
   long longvar;

   fpidx = fopen("index.txt", "r");
   if (!fpidx) {
       printf("error opening file\n");
       exit(1);
   }    
   for (j=0; j<25; j++) {
      idxrec[j] = (indexrecord *) malloc(sizeof(indexrecord));
      for (i=0; i<26; i++) {
         idxrec[j]->index[i] = (int) malloc(sizeof(int));
         idxrec[j]->index[i] = 0;
        }
        idxrec[j]->count = (long) malloc(sizeof(longvar));
        idxrec[j]->start = (long) malloc(sizeof(longvar));
      idxrec[j]->count = 0;
      idxrec[j]->start = 0;
   }

   for (j=0; j<23; j++) {
      for (i=0; i<26; i++) {
         fscanf(fpidx, "%d", &intvar);
         idxrec[j]->index[i] = intvar;
      }
      fscanf(fpidx, "%ld", &longvar);
      idxrec[j]->start = longvar;
        fscanf(fpidx, "%ld", &longvar);
        idxrec[j]->count = longvar;
        wordctr += longvar;
   }
   fclose(fpidx);
}
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Question by:ibo
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6 Comments
 
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Accepted Solution

by:
bbousquet earned 150 total points
ID: 2598658
Why are you using mallocs everywhere?

You just need to malloc each indexrecord structure once and store the pointer in your idxrec array. No need to allocate very single member from the structure.

[and don't forget to use free to deallocate the malloc'ed vars]

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LVL 3

Expert Comment

by:terajiv
ID: 2599119
Hi ibo,
see the code below
////////////////////////////////////////
for (j=0; j<25; j++) {
      idxrec[j] = (indexrecord *) malloc(sizeof(indexrecord));
      for (i=0; i<26; i++) {
         idxrec[j]->index[i] = (int) malloc(sizeof(int));
         idxrec[j]->index[i] = 0;
  }
  idxrec[j]->count = (long) malloc(sizeof(longvar));
  idxrec[j]->start = (long) malloc(sizeof(longvar));
      idxrec[j]->count = 0;
      idxrec[j]->start = 0;
   }
//////////////////////////////////////////
Here u have already allocated memory to the Structure by Typing
>>idxrec[j] = (indexrecord *) malloc(sizeof(indexrecord));

and after that again ur allocating memory to the same structure elements.

See when u allocate memory to Structure memory is allocated to the Members. So no need to Allocate it Seperately and this is the main cause of ur Problem Remove that and see u will get good Result.

Rajiv
0
 
LVL 2

Expert Comment

by:bbousquet
ID: 2599168
terajiv, that is EXACTLY what I just said above.

It is the custom around here to respond to questions with comments. The question asker will then decide which comment better answers his problem/question. That way, the question is not locked for others to answer.

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LVL 3

Author Comment

by:ibo
ID: 2600825
sorry terjiv but i have to give the credit to whoever gave the answer first.
comments are answers too.
0
 
LVL 3

Expert Comment

by:terajiv
ID: 2603148
Its ok...Actually I should say Sorry...
Anyway
The Imp thing is ur Problem is solved.

So Cheers
Rajiv
0
 
LVL 3

Author Comment

by:ibo
ID: 2604933
hi im back..
so what was left was

idxrec[j] = (indexrecord *) malloc(sizeof(indexrecord));

i replaced it with:
*idxrec = (indexrecord *) malloc(sizeof(indexrecord));

but it produced a core dump. it crashed.

sorry i didnt really tried the solution right away.. i just assumed it was the right thing.
actually i had my reason for allocating each element in the structure. i originally programmed this in turbo c, tried this way but didnt work.. so i was able to make it work only by allocating each of the elements. but now in linux it doesnt work.
help pls. im not yet very familiar with unix c.
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