Thread: sequential file program

"Total". I see it's in your Student struct, and from the assignment, it's not to be written to any file, but only computed.

I don't see why it would need to be in the struct then, and I'm removing it.

More later.

Here we go: Not everything, but it's a good start. We need your new transaction data, when you're ready.

Code:

/*Modifications of a program posted by needHelpBad, by Adak */

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

struct Student {
    int  key;
    char name [7];
    int  test1, test2, test3;
    int  hwCount;
    int  hwPoints;
} 
dummy = {-1, "", 0, 0, 0, 0, 0},
* aStudent;  //this is the weirdest bit of code I've seen in awhile. What is up with it?

FILE * infile, * recordFile, * transFile;

int openFiles ( ) {
    if ((infile = fopen ("seq_data.txt", "r")) == NULL) {
	   fprintf (stderr, "Error in opening input file\n");
	   return 1;
    }
    if ((transFile = fopen ("seq_tran.txt", "r")) == NULL) {
	   fprintf (stderr, "Error in opening transaction file\n");
	   return 1;
    }


    if ((recordFile = fopen ("seq_recs.txt", "w+b")) == NULL) {
	   fprintf (stderr, "Error in opening record file\n");
	   return 1;
    }
    return 0;
}

void closeFiles ( ) {
    fclose (infile);
    fclose (recordFile);
    fclose(transFile);
}

struct Student * getOneStudentFromData ( ) {
   struct Student * aStudentPtr;
   int scanned, theId, theTest1, theTest2, theTest3, theHwCount, theHwPoints;
   char theName [7];
   char cr;
   fscanf (infile, "&#37;d%s%d%d%d%d%d%c",
	&theId, theName, &theTest1, &theTest2, &theTest3,
	&theHwCount, &theHwPoints, &cr);

   if(theId > 0)   {
      aStudentPtr = (struct Student *) malloc (sizeof (struct Student));
      aStudentPtr->key = theId;
      aStudentPtr->test1 = theTest1;
      aStudentPtr->test2 = theTest2;
      aStudentPtr->test3 = theTest3;
      aStudentPtr->hwCount = theHwCount;
      aStudentPtr->hwPoints = theHwPoints;
      strcpy (aStudentPtr->name, theName);    
   }
   else 
      aStudentPtr = &dummy;

   return aStudentPtr;
}

void writeRecord (struct Student * theStudentPtr) {
   fwrite (theStudentPtr, sizeof (struct Student), 1, recordFile);
}

struct Transaction {
   int type;		
   int key;		
   int value;	
   char name [7];
};


int readDataAndWriteRecords (void) {
   static int recordsSeen = 0;	
   struct Student * theStudentPtr;

   theStudentPtr = (struct Student *) malloc (sizeof (struct Student));

   do {
	   theStudentPtr = getOneStudentFromData ( );
      if(theStudentPtr->key == -1)  {
         theStudentPtr = &dummy;
         recordsSeen--;
      }
	   recordsSeen ++;
	   writeRecord (theStudentPtr);
   } while (theStudentPtr->key != -1);

   return recordsSeen;
}

int readRecordsAndPrintData ( ) {
   static int recordsSeen = 0;
   struct Student * myStudentPtr;

   myStudentPtr = (struct Student *) malloc (sizeof (struct Student));
   putchar('\n');
   do {
   	fread (myStudentPtr, sizeof (struct Student), 1, recordFile);
    	
      if (myStudentPtr->key != -1) {
	      printf ("%d\t%s\t%d\t%d\t%d\t%d\t%d\n",
         myStudentPtr->key,
		   myStudentPtr->name,
		   myStudentPtr->test1,
		   myStudentPtr->test2,
         myStudentPtr->test3,
		   myStudentPtr->hwCount,
		   myStudentPtr->hwPoints);
         recordsSeen++;
	   }	
   } while (myStudentPtr->key != -1);

   return recordsSeen;
}

int main ( ) {
   int i, numRecords, gar;

   for(i = 0; i < 10; i++)
      putchar('\n');

   if (openFiles ( )) 
	   return 1;
    
   numRecords = 0;
   numRecords = readDataAndWriteRecords ( );
   printf ("\n %d records read from data file\n", numRecords);

   fseek (recordFile, 0, SEEK_SET);

   numRecords = 0;
   numRecords = readRecordsAndPrintData ( );
   printf ("\n %d records read from record file\n", numRecords);
   closeFiles ( );
   printf("\n                   Program Complete - Press Enter When Ready");
   gar = getchar(); gar++;
   return 0;
}

Question to a more experienced programmer: Shouldn't these while loops which include malloc at the top of the loop, also include free at the bottom of the while loop, to stop memory leaking?

Also, isn't there something wrong with dummy having an extra pointer?

in the function
readDataAndWriteRecords you DO have a memory leak - malloced memory before do loop is leaked...

maybe you have other leaks... I haven't read the code till the end

Originally Posted by needhelpbad

so how would I go about fixing the loop in the readDataAndWriteRecords function

What do YOU think? Do you understand the concept of memory leaks?

--
Mats

Originally Posted by needhelpbad

bump.. ^^

Instead of annoying people with senceless bumping - write some code and show some progress. Do not wait for people to do your work...