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#include<stdio.h>
#include<string.h>
#define MAXLINES 5000
#define MAXLEN 1000
#define ALLOCSIZE 10000
char *lineptr[MAXLINES];
static char allocbuf[ALLOCSIZE];
static char *allocp = allocbuf;
int readlines(char *lineptr[], int nlines);
void writelines(char *lineptr[], int nlines);
int getline(char *, int);
char *alloc(int);
void qsort(char *lineptr[], int left, int right);
void swap(char *v[], int i, int j);
int main()
{
int nlines;
if(( nlines = readlines(lineptr, MAXLINES)) >= 0)
{
qsort(lineptr, 0, nlines-1);
writelines(lineptr, nlines);
return 0;
}
else
{
printf("Erro: input too big to sort\n");
return 1;
}
}
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]);
}
void qsort(char *v[], int left, int right)
{
int i, last;
if(left >= right) return;
swap(v, left, (left + right)/2);
last = left;
for(i = left+1; i <= right; i++)
if (strcmp(v[i], v[left]) < 0)
swap(v, ++last, i);
swap(v, left, last);
qsort(v, left, last-1);
qsort(v, last+1, right);
}
void swap(char *v[], int i, int j)
{
char *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
char *alloc(int n)
{
if(allocbuf + ALLOCSIZE - allocp >= n)
{
allocp += n;
return allocp -n;
}
else
return 0;
}
int getline(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;
}
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