#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* #define DEBUG */
#if defined(DEBUG)
#include "xmalloc.h"
#else
#define xmalloc(x, y) malloc(x)
#define xfree(x, y) free(x)
#define xrealloc(x, y, z) realloc(x, y)
#define xmallocdump()
#endif
#define ID_GETLINE 1001
#define ID_NODE 1002
#define BUFFSIZE 1024 /* >= 2 */
char *mygetline(FILE *fp) {
static char inbuff[BUFFSIZE];
char *outbuff_malloc, *tmpbuff;
char *p, *r;
int fEOL;
if ((outbuff_malloc = xmalloc(1, ID_GETLINE)) == NULL) {
return NULL;
}
*outbuff_malloc = '\0';
fEOL = 0;
do {
r = fgets(inbuff, BUFFSIZE, fp);
if (r == NULL)
break;
for (p = inbuff; *p != '\0'; p++)
;
if (*(p - 1) == '\n')
fEOL = 1;
if ((tmpbuff = xrealloc(outbuff_malloc, strlen(outbuff_malloc) + strlen(inbuff) + 1, ID_GETLINE)) == NULL) {
xfree(outbuff_malloc, ID_GETLINE);
return NULL;
}
strcat(tmpbuff, inbuff);
outbuff_malloc = tmpbuff;
} while (!fEOL);
if (strlen(outbuff_malloc) > 0) {
for (p = outbuff_malloc; *p != '\0'; p++)
;
if (*(p - 1) == '\n')
*(p - 1) = '\0';
return outbuff_malloc;
}
xfree(outbuff_malloc, ID_GETLINE);
return NULL;
}
struct node {
void *data;
struct node *left, *right;
};
void *push(struct node **root, void *data, int (*cmp)(void *, void *)) {
struct node *p;
if (!*root) {
if ((p = xmalloc(sizeof(struct node), ID_NODE)) == NULL) {
fprintf(stderr, "cannot allocate enough memory(struct node), aborted\n");
exit(-1);
}
p->data = data;
p->left = p->right = NULL;
*root = p;
return data;
}
if ((*cmp)(data, (*root)->data) < 0) {
return push(&((*root)->left), data, cmp);
} else {
return push(&((*root)->right), data, cmp);
}
}
void *pop(struct node **root) {
struct node *p;
void *data;
if (*root == NULL) {
return NULL;
}
if ((*root)->left) {
data = pop(&((*root)->left));
return data;
}
p = *root;
data = p->data;
*root = p->right;
xfree(p, ID_NODE);
return data;
}
int cmp_ascent(char *p, char *q) {
return strcmp(p, q);
}
int cmp_descent(char *p, char *q) {
return -strcmp(p, q);
}
int main(int argc, char *argv[]) {
struct node *root;
char *p;
int (*cmp)(char *, char *);
if (argc != 2) {
label_usage:
fprintf(stderr, "usage: %s <option>\n", argv[0]);
fprintf(stderr, "option: -a: ascent, -d: descent, input/output: stdio\n");
return 1;
}
if (*argv[1] == '-' && *(argv[1] + 1) == 'a')
cmp = cmp_ascent;
else if (*argv[1] == '-' && *(argv[1] + 1) == 'd')
cmp = cmp_descent;
else
goto label_usage;
root = 0;
while ((p = mygetline(stdin)) != 0)
push(&root, p, (int (*)(void *, void *))cmp);
while ((p = pop(&root)) != 0) {
printf("%s\n", p);
xfree(p, ID_GETLINE);
}
xmallocdump();
return 0;
}
/* end */