Originariamente inviato da oregon
Sistema il codice che così non si capisce nulla ...
E poi, in
Mqsort(lineptr, 0, nstr );
nstr
da dove viene?
codice:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXLINES 1000
#define ALLOCSIZE 10000
#define MAXLEN 1000
char *lineptr[MAXLINES]; /* puntatore alle linee di testo */
int readlines(char lineptr[], int nlines);
void writelines(char *lineptr[], int nlines);
void Mqsort (char *lineptr[], int left, int right);
int Mgetline(char s[], int lim );
void Mswap (char *v[], int i, int j);
int main()
{
int nlines ;
if ((nlines = readlines(lineptr, MAXLINES)) >= 0 )
{
Mqsort(lineptr, 0, nstr );
writelines(lineptr, nlines);
return 0 ;
}
else
{
printf("errore: troppe linee di input da ordinare\n");
return 1 ;
}
}
int readlines(char *lineptr[], int maxlines )
{
int len;
int nlines = 0;
char *p;
int nstr ;
char line[MAXLEN];
while ((len = Mgetline(line,MAXLEN)) > 0 )
if (nlines >= maxlines || (p = malloc(len)) == NULL)
return -1 ;
else
{
line[len-1] = '\0';
strcpy(p, line);
lineptr[nlines++] = p;
nstr = nlines ;
}
}
/* getline: carica una linea in s, ritorna la lunghezza */
int Mgetline(char s[], int lim )
{
int c, i;
i= 0;
while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
s[i++] = c ;
if (c == '\n')
s[i++] = c;
s[i] = '\0';
return i;
}
/* qsort : ordina v[left] ... v[right] in ordine crescente */
void Mqsort( char *v[], int left, int right )
{
int i, last;
int nlines;
if (left >= right)
return;
Mswap(v, left, (left + right) / 2 );
last = left;
for (i= left+1; i <= right; i++)
if (strcmp (v[i] , v[left]) < 0 )
Mswap(v, ++last, i);
Mswap(v, left, last);
Mqsort(v, left, last - 1);
Mqsort(v, last + 1, right);
}
/* swap : scambia v[i] con v[j] */
void Mswap (char *v[], int i, int j)
{
char *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
/* writelones scrive in output le linee */
void writelines(char *lineptr[], int nlines)
{
int i;
for (i = 0; i < nlines; i++ )
printf("%s\n", lineptr[i]);
}
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