//"Solution" for 5-14 from K&R
//From "The C Answer Book" by Tondo and Gimpel

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

#define NUMERIC 1
#define DECR 2
#define LINES 100

int numcmp(char *, char *);
int readlines(char *lineptr[], int maxlines);
void qsort(char *v[], int left, int right,
	int (*comp)(void *, void *));
void writelines(char *lineptr[], int nlines, int decr);

static char option = 0;

main(int argc, char *argv[]){
  char *lineptr[LINES];
  int nlines = 0;
  int c, rc = 0;

  while (--argc > 0 && (*++argv)[0] == '-')
    while (c = *++argv[0])
      switch (c){
        case 'n':
          option |= NUMERIC;
          break;
        case 'r':
          option |= DECR;
          break;
        default:
          printf("sort: illegal option %c\n", c);
          argc = 1;
          rc = -1;
          break;
      }

      if(argc)
        printf("Usage: sort -nr \n");
      else
        if ((nlines = readlines(lineptr, LINES)) > 0){
          if (option & NUMERIC)
            qsort((void **) lineptr, 0, nlines-1,
              (int (*) (void *, void *)) numcmp);
          else
            qsort((void **) lineptr, 0, nlines-1,
              (int (*) (void *, void *)) strcmp);
          writelines(lineptr, nlines, option & DECR);
        }else{
          printf("input too big to sort \n");
          rc = -1;
        }
  return rc;
}

void writelines(char *lineptr[], int nlines, int decr){
  int i;
  
  if(decr)
    for(i = nlines-1; i>=0; i--)
      printf("%s\n", lineptr[i]);
  else
    for(i = 0; i<nlines; i++)
      printf("%s\n", lineptr[i]);
}

//readlines, numcmp from book go here