string reversal

[Unregistered]

Can somebody tell me why this only reverses the last word in the data file, and not all the texti in the file?

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

int main(void)
{
	FILE *datain, *dataout;

	char filenamein[15], filenameout[15], str[] = "";

	printf("Enter input filename: ");
	gets(filenamein);
	printf("Enter output filename: ");
	gets(filenameout);

	datain = fopen(filenamein, "r");
	dataout = fopen(filenameout, "w");
		
	while (! feof(datain))
	
	fscanf(datain, "%s", str);
	fprintf(dataout,strrev(str));
return 0;
}

[-KEN-]

I could, but then I'd have to kill you

[-KEN-]

Well, either that or I could ask you to review loops





ooooh...that and look up the fucntion fclose()

[Unregistered]

ok. I got that part, but what about spaces

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

int main(void)
{
	FILE *datain, *dataout;

	char filenamein[15], filenameout[15], str[] = "";

	printf("Enter input filename: ");
	gets(filenamein);
	printf("Enter output filename: ");
	gets(filenameout);

	datain = fopen(filenamein, "r");
	dataout = fopen(filenameout, "w");
		
	while (! feof(datain))
	{	
		fscanf(datain, "%s", str);
		fprintf(dataout,strrev(str));
	}
	fclose(datain);
	fclose(dataout);
		
	
return 0;
}

i have this in my input:

this is a test

this is the output i get. It is all in one big sting with no spaces.

sihtsiatset

[Unregistered]

ok i got it.

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

int main(void)
{
	FILE *datain, *dataout;

	int x = 100000000;
	char filenamein[15], filenameout[15], str[] = "";

	printf("Enter input filename: ");
	gets(filenamein);
	printf("Enter output filename: ");
	gets(filenameout);

	datain = fopen(filenamein, "r");
	dataout = fopen(filenameout, "w");
		
	while (! feof(datain))
	{		
		fgets(str, x, datain);
		fprintf(dataout,strrev(str));
	}
	fclose(datain);
	fclose(dataout);
		
	
return 0;
}

Can somebody help me with the code for x though, so x can be infinite. I tried using x++ within the while loop, but it screwed up the letters.

[Unregistered]

the x in fgets only refers to the number of characters maximum to read on that line, and since in general integers are maximum of about 65535 (unsigned) or something like that so if your lines in the file are 100000000 characters long then i recommend declaring your x variable like:
long x = 100000000;

or decrease the size of x to somethin like:
int x = 32000;

[Shiro]

What if this fails?

datain = fopen(filenamein, "r");
dataout = fopen(filenameout, "w");

You should check if the pointers returned by fopen are not NULL.

[Prelude]

>gets(filenamein);
Never use gets, it's unsafe to the extreme. Use fgets instead.
fgets ( filenamein, sizeof filenamein, stdin );

-Prelude