Thread: How do i sort that file after merge

Hi im a beginner programmer. Im trying to put two files together into a third file and have it sorted. I have success on putting the two files together but they still wont get sorted even though I have the if else statements in there. Can someone tell me what im doing wrong because i dont. here is my code....

Code:

	#include <stdio.h>
#include <limits.h>

#define READ_MODE "rb"
#define WRITE_MODE "wb"

int main (void)
{
	FILE *fpM1;
	FILE *fpM2;
	FILE *fpOut;

	int recM1;
	int recM2;

	char file1ID[]   = "P13Mrg1.bin";
	char file2ID[]   = "P13Mrg2.bin";
	char fileOutID[] = "P13Mrg3.bin";
	int sentinel     = INT_MAX;
	int mergeCnt     = 0;

	printf("begin File Merge:\n");
	if(!(fpM1 = fopen (file1ID, READ_MODE)))
	printf("\aError on %s\n",file1ID);

	if(!(fpM2 = fopen (file2ID, READ_MODE)))
	printf("\aError on %s\n",file2ID);

	if(!(fpOut = fopen (fileOutID, WRITE_MODE)))
	printf("\aError on %s\n",fileOutID);

	fread (&recM1, sizeof(int),1,fpM1);
	if (feof(fpM1))
		recM1 = sentinel;

	fread (&recM2, sizeof(int),1,fpM2);
	if (feof(fpM2))
		recM2 = sentinel;

	while(!feof(fpM1) || !feof(fpM2))
	{
		if(recM1<= recM2)
		{
			fwrite(&recM1,sizeof(int),1,fpOut);
			mergeCnt++;
			fread (&recM1,sizeof(int),1,fpM1);
			if (feof(fpM1))
			recM1=sentinel;
		}
		else
		{
			fwrite(&recM2, sizeof(int),1,fpOut);
			mergeCnt++;
			fread(&recM2,sizeof(int),1,fpM2);
			if (feof(fpM2))
				recM2 = sentinel;
		}
	}
	fclose (fpM1);
	fclose(fpM2);
	fclose (fpOut);
printf("End File Merge. %d items merged.\n",mergeCnt);
return 0;
}

THANK YOU!

Can you be more specific about what is going wrong?

On the face of it, it doesn't look too far off working

You're sure that you wrote your ints to your input files using fwrite and not fprintf

yeah im pretty sure that everything is okay with this code syntax wise. The program should result in the third file being sorted from smallest number to largest number.... can anyone try it, ive asked like 10 people already and no one understands how to do it.....can someone please help me out. THank YOu.

Your algorithm looks incorrect to me.

Do the following:
1.) Read all the data in file1 into memory (Array or Linked List)
2.) Read all the data in file2 into memory (Array or Linked List)
3.) Sort the values got from the above 2 steps and store them somewhere.
4.) Write the stored result to the file3

shaik786 and breed have missed the point
The input files are already sorted - you only need read the next record from each file and decide which one to output when doing a merge.

As for unregistered
No idea - it works here - compiled with DJGPP
Perhaps you need to post how you created your two input files.

However, having re-read your original post, perhaps shaik786 and breed are onto something.
You don't actually state that your input files are sorted.
You have to have sorted your input files for a merge to work.