Thread: Explanation Please

Could someone out there explain this code. I have placed "/* explain */ " next to the statements that I have no clue has to what or how they work.

thanks

Code:

#include <stdio.h> 
#include <dir.h> 
#include <string.h> 
#define ALL_ATTS  (FA_DIREC | FA_ARCH) /* explain */ 

void walker(const char *, const char *);


int main(void)
{
  const char *root = "\\";
  char buf[BUFSIZ];
  char * line_ptr;
  
  printf ("buf size: %d\n", sizeof(buf)); 
  printf ("This program will find a file on the current drive.\n"
          "Enter the name of the file to look for: ");

  fflush(stdout);  

  if (fgets(buf, sizeof(buf), stdin))
  {
    strtok(buf, "\n");
    
    line_ptr = buf;
    printf ("buf: %s\n", line_ptr);
    printf ("buf: %s\n", buf);
    
    walker(root, buf);
  }
  
  return(0);
}

void walker(const char *path, const char *findme)
{
  struct ffblk  finder;/* explain */ 
  unsigned int  res;

  chdir(path);

/* explain */ 
  for (res = findfirst("*.*", &finder, ALL_ATTS); res == 0; res = findnext(&finder)) /* explain */ 
  {
    if (strcmp(finder.ff_name, ".") == 0) continue;   /* explain */ 
    if (strcmp(finder.ff_name, "..") == 0) continue;  /* explain */ 

    if (finder.ff_attrib & FA_DIREC) /* explain */ 
    {
      char newpath[MAXPATH];
      strcpy(newpath, path);
      strcat(newpath, "\\"); 
      strcat(newpath, finder.ff_name);
      chdir(finder.ff_name); /* explain */ 
      walker(newpath, findme);
      chdir(".."); /* explain */ 
    }
    else
    {
      if (strcmp(finder.ff_name, findme) == 0)
      {
        printf("Found in: %s\n", path);
      }
    }
  }
}

Code:

#include <stdio.h> 
#include <dir.h> 
#include <string.h> 
#define ALL_ATTS  (FA_DIREC | FA_ARCH) /* explain */

basicly he is saying ALL_ATTS is the same as FA_DIREC and FA_ARCH. Like when one does a open() wiht multipule flags

Code:

void walker(const char *path, const char *findme)
{
  struct ffblk  finder;/* explain */

Im not gonna tell you but look at how a structur is definded

struct name
{
variables
} tag;

Code:

  chdir(path);

/* explain */

man chdir.. the name really is really explaniatory

Code:

  for (res = findfirst("*.*", &finder, ALL_ATTS); res == 0; res = findnext(&finder)) /* explain */

Look at for loops, its really strate forward.

Code:

  {
    if (strcmp(finder.ff_name, ".") == 0) continue;   /* explain */ 
    if (strcmp(finder.ff_name, "..") == 0) continue;  /* explain */

What are you look for here? they are plain if statements

Code:

    if (finder.ff_attrib & FA_DIREC) /* explain */ 
    {
      char newpath[MAXPATH];
      strcpy(newpath, path);
      strcat(newpath, "\\"); 
      strcat(newpath, finder.ff_name);
      chdir(finder.ff_name); /* explain */ 
      walker(newpath, findme);
      chdir(".."); /* explain */

the if(finder.ff_attrib & FA_DIREC) is testing to see if the flag FA_DIREC is set.

the chdir()'s are explaind in the man pages.

Thanks Squid,

I am mostly stuck on:

What is this, where did it come from and what does it do: ALL_ATTS (FA_DIREC | FA_ARCH)

I know about structs but where did ffblk come from
struct ffblk finder

and what is it and what is the relationship that allows finder to link with
finder.ff_name
finder.ff_attrib

Where did findfirst and findnext come from? I do not see in the code where they are defined.

I'm lost because I see a lot of variable names that I cannot see where they come from and how they work together.