[SOLVED] C

GamezR2EZ · 03-06-2012, 08:37 AM

I have run into a bit of an impasse with a project I am working on. I need to open up a varying number of files and compare them to one another in sections.

The code below works and does a basic version of what I need. I wrote this quickly:

Code:

int main(int argv, char *argc[])
{
  int A, B, i, i2, x, sz1, sz2; //2 separate bytes
  unsigned char buffer1[2532]; 
  unsigned char buffer2[2532];
  FILE *test1, *test2;
  
  if(argv <= 1){
    printf("This program needs a minimum of 2 files\n");
    return 1;
  }
  
  test1 = fopen(argc[1], "rb");
  test2 = fopen(argc[2], "rb");
  
  fseek(test1, 0L, SEEK_END);
  sz1 = ftell(test1);
  fseek(test1, 0L, SEEK_SET);
   
  fseek(test2, 0L, SEEK_END);
  sz2 = ftell(test2);
  fseek(test2, 0L, SEEK_SET);
  
  int numFrames = (sz1/2352);
  
  bool framesdiff[numFrames];
  
  for(i=0; i<(numFrames); i++){
    framesdiff[i] = 0;
  }
  
  for(i=0; i<(numFrames); i++){
    fread(&buffer1, 2532, 1, test1);  
    fread(&buffer2, 2532, 1, test2);
  
    for(i2=0; i2<2532; i2++){
      if(buffer1[i2] == buffer2[i2])
      {
	//printf("They match!\n");
      } else {
	framesdiff[i] = 1;
	break;
	//printf("He's dead Jim!\n");
      }
    }
    //printf("%X\n", framesdiff[i]);
  }
  
  for(i=0; i<(numFrames); i++){
    if(framesdiff[i] == 1){
      printf("Frame %d differs\n", i+1);
    }
  }
  
  //printf("Size 1: %d\nSize 2: %d\n%d %d\n", sz1, sz2, i , i2);
  
  fclose(test1);
  fclose(test2);
  
  return 0;
}

Now I need to open a varying number of files and do essentially the same thing. The comparing part I have not worked on, the opening multiple files I need help with. I just don't see the code. The only thing I can figure would be something like this (I know this will not work):

Code:

for(i=1;i<argv;i++){
  FILE *fp(i) = fopen(argc[1], "rb");
}

Where the FILE variables would be fp1, fp2, fp3, ect..

Now I am aware that will not work, but it demonstrates my current approach.

Please give me some ideas of how to proceed. This is a learning project for me, so I also appreciate direction instead of outright answers if you have any advice (I can learn from both).

The platform I am working on is Linux.

---Solution---

I was just tired.

Code:

FILE *fp[argv-1];

for (i=0; i<(argv-1); i++){
  fp[i] = fopen(argc[i+1], "rb");
  fclose(fp[i]);
}

NevemTeve · 03-06-2012, 09:24 AM

correction:

Code:

FILE *f[argc-1];

for (i=0; i<argc-1; i++) {
    f[i] = fopen (argc[i+1], "rb");
    if (! f[i]) /* error */
}

GamezR2EZ · 03-07-2012, 06:42 AM

Thanks, that's it. That is what I get for working on a problem when I am to tired to stand.
Also, while argv[0] (as an array) isn't correct argv (as an int) most certainly is. It holds the number of parameters starting at 1.

Good news is I got the comparing part done while I took a break from this simple solution.

Found your post helpful, updated first post, marked as solved, ect.

Code:

FILE *fp[argv-1];

for (i=0; i<(argv-1); i++){
  fp[i] = fopen(argc[i+1], "rb");
  fclose(fp[i]);
}

NevemTeve · 03-07-2012, 07:15 AM

Off:

Well, you use 'argc' and 'argv' in an unique way, the general usage is:

Code:

int main (int argc, char *argv[]);

c=count, v=vector

GamezR2EZ · 03-07-2012, 08:19 AM

I definitively do, I have been messing around with C for years and learned argc/argv backwards. Now I never remember what is the correct (read: standard) way. I always just reference the way it is written in the program I am working on.

I will try to remember v=vector in the future, but old habits die hard.

I either case, this program is doing exactly what I needed!

Thanks again.