Programming

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

char filenames[50000] = "";

int list(const char *name, const struct stat *status, int type)
{
    if( (type == FTW_F) && strstr(name, ".txt") && !strstr(name, ".c") )
    {
        sprintf(filenames + strlen(filenames), "%s,", name);
     }

    return 0;
}

int main(void)
{
    ftw("/path-to-directory", list, 1); // recursively buffer file names in directory

    char input[25] = "keyword1+keyword2+"; // no buffer overflow here...

    char filecontent[50000] = ""; // I checked, only about 25000 chars are used
    char filematches[50000] = "";

    size_t length = 0;

    FILE *file1;

    const char *line = strtok(filenames, ","); // file names separated by commas
    const char *keyword = strtok(searchstring, "+"); // key words separated by plus signs
    while(line != NULL)
    {
        file1 = fopen(line, "r");
        if (file1 != NULL)
        {
                length = fread(filecontent, 1, 49999, file1);
                fclose(file1); 
       }else{
            printf("fopen failed at: %s", line);
            exit(1);
        }

        filecontent[length] = '\0';

        while(keyword != NULL)
        {
            if(strstr(filecontent, keyword))
            {
                sprintf(filematches + strlen(filematches), "%s\n", line); // buffer file names that include at least one keyword
                break; // one keyword is in the file, no need to check for more
            }
            keyword = strtok(NULL, "+");
        }

        filecontent[0] = '\0';
        keyword = strtok(searchstring, "+"); // restart strtok to beginning of searchstring
        line = strtok(NULL, ","); // this is (null) after first run
    }
printf("filematches: %s\n", filematches);
    return 0;
}

#include <string.h>
#include <stdlib.h>
#define SZ 128  // fix this for your needs
static char hold[SZ];

char **foo( char **dest, const char *src, int *elems, const char *delims)
{
    int i=0;
    char *p=NULL;
    
    dest[0]=NULL;
    strcpy(hold, src);
    p=strtok(hold, delims);
    while(p!=NULL)
    {
       dest[i++]=p;
       dest[i]=NULL;
       p=strtok(NULL, delims);       
    }
    *elems=i;
    return dest;
}

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

char filenames[500][256]; // use your local file length limit
int  filecount = 0;

int list(const char *name, const struct stat *status, int type)
{
  if( (type == FTW_F) && strstr(name, ".txt") && !strstr(name, ".c") )
  {
    snprintf (filenames[filecount], 255, "%s", name);
    filecount++;
  }

  return 0;
}

int main(void)
{ 
  // recursively buffer file names in directory
  if ( 0 != ftw ("/path-to-directory", list, 1) )
  {
    fprintf (stderr, "error in ftw: %s\n", strerror (errno));
    return (-1);
  }

  
  for ( int i = 0; i < filecount; i++ )
  {
    printf ("%3d :  %s\n", i, filenames[i]);
  }

  return 0;
}