Exercise 5.16 - -d makes comparison on letters, numbers, blanks#
Question#
Add the -d (directory order) option, which makes comparisons only on
letters, numbers and blanks. Make sure it works in conjunction with -f.
/* Add the -d ("Directory option") which makes comparision only on letters, numbers and blanks.
Make sure it works in conjunction with -f */
#include<stdio.h>
#include<ctype.h>
#define NUMERIC 1 /* numeric sort */
#define DECR 2 /* sort in decreasing order */
#define FOLD 4 /* fold upper and lower cases */
#define MDIR 8 /* directory order */
#define LINES 100 /* maximum number of lines to be sorted */
int charcmp(char *,char *);
int numcmp(char *,char *);
int readlines(char *lineptr[],int maxlines);
void myqsort(void *v[],int left,int right,int (*comp)(void *,void *));
void writelines(char *lineptr[],int nlines,int order);
static char option = 0;
/* sort input lines */
int main(int argc,char *argv[])
{
char *lineptr[LINES]; /* pointer to text line */
int nlines;
int c,rc=0;
while(--argc > 0 && (*++argv)[0] == '-')
while(c = *++argv[0])
switch(c)
{
case 'd': /* directory order */
option |= MDIR;
break;
case 'f':
option |= FOLD;
break;
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 -dfnr \n");
else
{
if((nlines = readlines(lineptr,LINES)) > 0)
{
if(option & NUMERIC)
myqsort((void **)lineptr,0,nlines-1,(int (*)(void *,void *))numcmp);
else
myqsort((void **)lineptr,0,nlines-1,(int (*)(void *,void *))charcmp);
writelines(lineptr,nlines,option & DECR);
}
else
{
printf("input too big to sort \n");
rc = -1;
}
}
return rc;
}
/* charcmp: return <0 if s < t, 0 if s ==t, >0 if s > t */
int charcmp(char *s,char *t)
{
char a,b;
int fold = (option & FOLD)? 1:0;
int dir = (option & MDIR)? 1: 0;
do
{
if(dir)
{
while(!isalnum(*s) && *s != ' ' && *s != '\0')
s++;
while(!isalnum(*t) && *t != ' ' && *t != '\0')
t++;
}
a = fold ? tolower(*s): *s;
s++;
b = fold ? tolower(*t): *t;
t++;
if(a==b && a == '\0')
return 0;
} while( a == b);
return a - b;
}
#include<stdlib.h>
/* numcmp: compare s1 and s2 numerically */
int numcmp(char *s1,char *s2)
{
double v1,v2;
v1 = atof(s1);
v2 = atof(s2);
if( v1 < v2)
return -1;
else if ( v1 > v2)
return 1;
else
return 0;
}
void swap(void *v[],int i,int j)
{
void *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
/* myqsort: sort v[left] ... v[right] into increasing order */
void myqsort(void *v[],int left,int right,int (*comp)(void *,void *))
{
int i,last;
void swap(void *v[],int,int);
if(left >= right) /* do nothing if array contains */
return; /* fewer than two elements */
swap(v,left,(left+right)/2);
last = left;
for(i = left + 1; i<=right;i++)
if((*comp)(v[i],v[left])<0)
swap(v,++last,i);
swap(v,left,last);
myqsort(v,left,last-1,comp);
myqsort(v,last+1,right,comp);
}
#define MAXLEN 1000 /* max length of any input line */
int mgetline(char *,int);
char *alloc(int);
/* readlines: read input lines */
int readlines(char *lineptr[],int maxlines)
{
int len,nlines;
char *p,line[MAXLEN];
nlines=0;
while((len = mgetline(line,MAXLEN)) > 0)
if(nlines >= maxlines || (p = alloc(len)) == NULL)
return -1;
else
{
line[len-1] = '\0';
strcpy(p,line);
lineptr[nlines++] = p;
}
return nlines;
}
/* writelines: write output lines */
void writelines(char *lineptr[],int nlines,int order)
{
int i;
if (order)
for( i = nlines -1; i >= 0; i--)
printf("%s\n",lineptr[i]);
else
for( i = 0; i < nlines; i++)
printf("%s\n",lineptr[i]);
}
#define ALLOCSIZE 10000 /* size of available space */
static char allocbuf[ALLOCSIZE]; /* storage for alloc */
static char *allocp = allocbuf; /* next free position */
char *alloc(int n) /* return pointer to n characters */
{
if ( allocbuf + ALLOCSIZE - allocp >= n)
{
allocp += n;
return allocp - n;
}
else
return 0;
}
void afree(char *p) /* free storage pointed to by p */
{
if( p >= allocbuf && p < allocbuf + ALLOCSIZE)
allocp = p;
}
/* mgetline: read a line s, return length */
int mgetline(char s[],int lim)
{
int c,i;
for(i=0;i<lim-1 && (c=getchar())!=EOF && c!='\n';++i)
s[i] = c;
if( c == '\n')
{
s[i] = c;
++i;
}
s[i] = '\0';
return i;
}