#1
  1. No Profile Picture
    Registered User
    Devshed Newbie (0 - 499 posts)

    Join Date
    Feb 2013
    Posts
    1
    Rep Power
    0

    Sort Program Help


    Hi, needing help with c programming. Im suppose to make a "poor mans" variation to the Sort function built into unix. The program is suppose to read in a file and sort the contents of the file. So its a variation of the Unix Sort feature. I have remade the readLine function we were provided so that it doesnt use fgets. I need help on where to go from here, Not sure on how to make a sort function. Here are the reqirements of the program:

    Code:
     Re-implement the readLine() function so that it no longer makes use of fgets(). Instead, process the input on a given line character-by-character.  Provide code which will create a data structure similar to argv to hold all of the words to be sorted. Use malloc() to ensure that each entry has just the required number of bytes needed to store the words. The final entry in your array should be the NULL pointer.  Implement a sort() function which will rearrange the words in sorted order. To swap two words in your array, note that only a pair of pointers need to move. The strings themselves, once established, will never move.

    Code:
    #include <stdio.h> #include <stdlib.h> #include <string.h>  #define MAX_LINES 1000   /* maximum number of reminders */ #define WORD_LENGTH 10      /* max length of reminder message */  int read_line(char str[], int n);  int main(int argc, char *argv[]) {     char *lines[MAX_LINES];     char line[WORD_LENGTH + 1];     bool lineOverflow;   /* not enough room in char array? */     int i, j, num_lines = 0;      fp = fopen(FILE_NAME, "r");     if (fp == NULL) {         fprintf(stderr, "Error: can't open %s for reading.\n", FILE_NAME);         exit(EXIT_FAILURE);     }      FILE *fp = fopen(argv[1], "r");     if (fp == NULL) { 	fprintf(stderr, "Error: can't open %s for reading.\n", argv[1]); 	exit(EXIT_FAILURE);     }      while(readLine(line, sizeof(line), fp, &lineOverflow) != NULL) { 	printf("%s", line);     }          fclose(fp);    } return(0); }      char *readLine(char *s, int n, FILE *fp, bool *overflow) {      int length;     int ch;     int skipped;     /* the number of NON-newline characters skipped over                      for lines too long to fit in the given char array */     int i = 0;      ch = getc(fp);   /* read a line */     if (ch == EOF) {       *overflow = false;       return NULL;    /* either stream is at eof or there was a read error */     }          while(ch != '\n' && i < (n - 1)) {       s[i++] = ch;       ch = getc(fp);     }          /* read was successful:  did we get the entire line? */     length = strlen(s);     if (s[length - 1] == '\n') {         s[length - 1] = '\0';    /* we don't want to store the newline */         *overflow = false;     }     else {         /* skip to end of current line */         skipped = 0;         while ((ch = getc(fp)) != '\n' && (ch != EOF))             skipped++;         *overflow = (skipped > 0);     }     return s; }   void Sort() {             }
  2. #2
  3. Contributed User
    Devshed Specialist (4000 - 4499 posts)

    Join Date
    Jun 2005
    Posts
    4,417
    Rep Power
    1871
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper

IMN logo majestic logo threadwatch logo seochat tools logo