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/* find -nx pattern */
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAXLINES 5000
#define MAXLEN 1000
#define ALLOCSIZE 10000
static char allocbuf[ALLOCSIZE];
static char *allocp = allocbuf;
char *lineptr[MAXLINES];
char *alloc(int n);
int readlines(char *lineptr[], int nlines);
void writelines(char *lineptr[], int nlines);
void qsort1(void *lineptr[], int left, int right, int (*comp) (void *, void *));
int numcmp(char *, char *);
int getline(char *line, int max);
void swap1(void *v[], int i, int j);
int main(int argc, char *argv[])
{
int nlines;
int numeric = 0;
if (argc > 1 && strcmp(argv[1], "-n") == 0) numeric=1;
if ((nlines = readlines(lineptr, MAXLINES)) >= 0)
{
qsort1((void**) lineptr, 0, nlines-1, (int (*)(void*,void*))(numeric ? numcmp : strcmp));
writelines(lineptr, nlines);
return 0;
}
else
{
printf("Input too big to sort\n");
return 1;
}
}
void qsort1(void *v[], int left, int right, int (*comp) (void *, void *))
{
int i, last;
if (left >= right) return;
swap1(v, left, (left+right)/2);
last = left;
for (i=left+1; i<=right; i++)
if ((*comp)(v[i], v[left]) < 0) swap1(v, ++last, i);
swap1(v, left, last);
qsort1(v, left, last-1, comp);
qsort1(v, last+1, right, comp);
}
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 swap1(void *v[], int i, int j)
{
char *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
int readlines(char *lineptr[], int maxlines)
{
int len, nlines;
char *p, line[MAXLEN];
nlines = 0;
while (( len = getline(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;
}
void writelines(char *lineptr[], int nlines)
{
int i;
for(i=0; i < nlines; i++)
printf("%s\n", lineptr[i]);
}
int getline(char *line, int max)
{
int c, i=0;
while(--max > 0 && (c=getchar()) != EOF && c!='\n')
{ *line++=c; i++; }
if(c=='\n')
{ *line++=c; i++; }
*line='\0';
return i;
}
char *alloc(int n)
{
if(allocbuf + ALLOCSIZE - allocp >= n)
{
allocp += n;
return allocp -n;
}
else
return 0;
}
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