Exercise 5.15 - fold upper and lower case together#
Question#
Add the option -f to fold upper and lower case together, so that case distinctions are not made during sorting; for example, a and A compare equal.
/* Add the option -f to fold upper and lower cases together, so that case
* distinctions are not made clearly during sorting;For eg:a and A compare equal
* */
#include<stdio.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
#define NUMERIC 1 /* numeric sort */
#define DECR 2 /* sort in decreasing order */
#define FOLD 4 /* fold upper and lower cases */
#define LINES 100 /* maximum numnber of lines to be sorted */
int charcmp(char *,char *);
int numcmp(char *,char *);
int readlines(char *lineptr[],int maxlines);
void myqsort(char *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]; /* pointers to text lines */
int nlines; /* number of input lines read */
int c,rc=0;
while(--argc > 0 && (*++argv)[0] == '-') {
while(c = *++argv[0])
switch(c)
{
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 -fnr \n");
else
{
if((nlines=readlines(lineptr,LINES)) > 0)
{
if(option & NUMERIC)
myqsort((char **)lineptr,0,nlines-1,(int (*)(void *,void *))numcmp);
else if (option & FOLD)
myqsort((char **)lineptr,0,nlines-1,(int (*)(void *,void *))charcmp);
else
myqsort((char **)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;
}
}
/* charcmp: return < 0 if s <t, =0 if s =t,> 0 if s > t */
int charcmp(char *s,char *t)
{
for(;tolower(*s) == tolower(*t);s++,t++)
if(*s == '\0')
return 0;
return tolower(*s) - tolower(*t);
}
/* 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;
}
#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'; /* delete newline */
strcpy(p,line);
lineptr[nlines++]=p;
}
return nlines;
}
/* myqsort: sort v[left] ... v[right] into increasing order */
void myqsort(char *v[],int left,int right, int (*comp)(void *,void *))
{
int i,last;
void swap(char *v[],int i,int j);
if(left>=right) /* do nothing if array contains */
return; /*fewer that 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);
}
/* swap: interchange v[i] and v[j] */
void swap(char *v[],int i,int j)
{
char *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
/* writelines: write output line */
void writelines(char *lineptr[],int nlines, int decr)
{
int i;
for(i=0;i<nlines;i++)
printf("%s\n",lineptr[i]);
}
#define ALLOCSIZE 1000 /* 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 */
{
if (p >= allocbuf && p < allocbuf + ALLOCSIZE)
allocp = p;
}
/* mgetline: read a line into 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;
}