開発環境
- OS X Lion - Apple(OS)
- Emacs、BBEdit - Bare Bones Software, Inc. (Text Editor)
- プログラミング言語: C
- Clang (コンパイラ)
プログラミング言語C 第2版 ANSI規格準拠 (B.W. カーニハン D.M. リッチー (著)、 石田 晴久 (翻訳)、共立出版)の第5章(ポインタと配列)、5.11(関数へのポインタ)、演習5-14を解いてみる。
その他参考書籍
- プログラミング言語Cアンサー・ブック 第2版 (クロビス・L．トンド、スコット・E．ギンペル(著)、矢吹 道郎(翻訳))
演習 5-14.
コード
sample.c
#include <stdio.h>
#include <string.h>
#define NUM 1
#define REV 2
#define MAXLINES 5000
char *lineptr[MAXLINES];
int readlines(char *[], int);
void writelines(char *[], int, int);
void my_qsort(void *[], int, int, int (*comp)(void *, void*));
int numcmp(char *, char *);
int main(int argc, char *argv[])
{
int nlines;
int option;
char c;
option = 0;
while (--argc > 0 && (*++argv)[0] == '-') {
while (c = *++argv[0]) {
switch(c) {
case 'n':
option |= NUM;
break;
case 'r':
option |= REV;
break;
default:
printf("invalid option %c\n", c);
break;
}
}
}
if((nlines = readlines(lineptr, MAXLINES)) >= 0) {
my_qsort((void **) lineptr, 0, nlines - 1,
(int (*)(void *, void*))((option & NUM) ? numcmp: strcmp));
writelines(lineptr, nlines, option);
return 0;
} else {
printf("input too big to sortn");
return 1;
}
}
void my_qsort(void *v[], int left, int right,
int (*cmp)(void *, void *))
{
int i, last;
void swap(void *v[], int, int);
if (left >= right) {
return;
}
swap(v, left, (left + right) / 2);
last = left;
for (i = left + 1; i <= right; i++) {
if ((*cmp)(v[i], v[left]) < 0) {
swap(v, ++last, i);
}
}
swap(v, left, last);
my_qsort(v, left, last - 1, cmp);
my_qsort(v, last + 1, right, cmp);
}
#include <stdlib.h>
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;
}
return 0;
}
void swap(void *v[], int i, int j)
{
void *temp;
temp = v[i];
v[i] = v[j];
v[j] = temp;
}
#define MAXLEN 1000
int my_getline(char *, int);
char *alloc(int);
int readlines(char *lineptr[], int maxlines)
{
int len, nlines;
char *p, line[MAXLEN];
nlines = 0;
while((len = my_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 option)
{
int i;
if (option & REV) {
for (i = nlines - 1; i >= 0; i--) {
printf("%s\n", lineptr[i]);
}
} else {
for (i = 0; i < nlines; i++) {
printf("%s\n", lineptr[i]);
}
}
}
int my_getline(char *s, int lim)
{
int c;
char *t;
t = s;
for (; (c = getchar()) != EOF && c != '\n'; s++) {
*s = c;
}
if (c == '\n') {
*s = c;
s++;
}
*s = '\0';
return s - t;
}
#define ALLOCSIZE 10000
char allocbuf[ALLOCSIZE];
char *allocp = allocbuf;
char *alloc(int n)
{
if (allocbuf + ALLOCSIZE - allocp >= n) {
allocp += n;
return allocp - n;
} else {
return 0;
}
}
入出力結果(Terminal)
$ cat sample.txt Ah Love! could you and I with Fate conspire To grasp this sorry Scheme of Things entire, Would not we shatter it to bits -- and then Re-mould it nearer to the Heart's Desire! ah love! could you and i with fate conspire to grasp this sorry scheme of things entire, would not we shatter it to bits -- and then re-mould it nearer to the heart's desire! 1 5 2 4 3 !@#$%Ah Love! could you and I with Fate conspire !@#$%To grasp this sorry Scheme of Things entire, !@#$%Would not we shatter it to bits -- and then !@#$%Re-mould it nearer to the Heart's Desire! !@#$%ah love! could you and i with fate conspire !@#$%to grasp this sorry scheme of things entire, !@#$%would not we shatter it to bits -- and then !@#$%re-mould it nearer to the heart's desire! $ ./a.out < sample.txt !@#$%Ah Love! could you and I with Fate conspire !@#$%Re-mould it nearer to the Heart's Desire! !@#$%To grasp this sorry Scheme of Things entire, !@#$%Would not we shatter it to bits -- and then !@#$%ah love! could you and i with fate conspire !@#$%re-mould it nearer to the heart's desire! !@#$%to grasp this sorry scheme of things entire, !@#$%would not we shatter it to bits -- and then 1 2 3 4 5 Ah Love! could you and I with Fate conspire Re-mould it nearer to the Heart's Desire! To grasp this sorry Scheme of Things entire, Would not we shatter it to bits -- and then ah love! could you and i with fate conspire re-mould it nearer to the heart's desire! to grasp this sorry scheme of things entire, would not we shatter it to bits -- and then $ ./a.out -r < sample.txt would not we shatter it to bits -- and then to grasp this sorry scheme of things entire, re-mould it nearer to the heart's desire! ah love! could you and i with fate conspire Would not we shatter it to bits -- and then To grasp this sorry Scheme of Things entire, Re-mould it nearer to the Heart's Desire! Ah Love! could you and I with Fate conspire 5 4 3 2 1 !@#$%would not we shatter it to bits -- and then !@#$%to grasp this sorry scheme of things entire, !@#$%re-mould it nearer to the heart's desire! !@#$%ah love! could you and i with fate conspire !@#$%Would not we shatter it to bits -- and then !@#$%To grasp this sorry Scheme of Things entire, !@#$%Re-mould it nearer to the Heart's Desire! !@#$%Ah Love! could you and I with Fate conspire $ ./a.out -n < sample.txt re-mould it nearer to the heart's desire! !@#$%re-mould it nearer to the heart's desire! To grasp this sorry Scheme of Things entire, Ah Love! could you and I with Fate conspire Re-mould it nearer to the Heart's Desire! !@#$%Ah Love! could you and I with Fate conspire to grasp this sorry scheme of things entire, !@#$%To grasp this sorry Scheme of Things entire, !@#$%would not we shatter it to bits -- and then !@#$%Would not we shatter it to bits -- and then ah love! could you and i with fate conspire !@#$%Re-mould it nearer to the Heart's Desire! Would not we shatter it to bits -- and then !@#$%ah love! could you and i with fate conspire would not we shatter it to bits -- and then !@#$%to grasp this sorry scheme of things entire, 1 2 3 4 5 $ ./a.out -nr < sample.txt 5 4 3 2 1 !@#$%to grasp this sorry scheme of things entire, would not we shatter it to bits -- and then !@#$%ah love! could you and i with fate conspire Would not we shatter it to bits -- and then !@#$%Re-mould it nearer to the Heart's Desire! ah love! could you and i with fate conspire !@#$%Would not we shatter it to bits -- and then !@#$%would not we shatter it to bits -- and then !@#$%To grasp this sorry Scheme of Things entire, to grasp this sorry scheme of things entire, !@#$%Ah Love! could you and I with Fate conspire Re-mould it nearer to the Heart's Desire! Ah Love! could you and I with Fate conspire To grasp this sorry Scheme of Things entire, !@#$%re-mould it nearer to the heart's desire! re-mould it nearer to the heart's desire! $ ./a.out -n -r < sample.txt 5 4 3 2 1 !@#$%to grasp this sorry scheme of things entire, would not we shatter it to bits -- and then !@#$%ah love! could you and i with fate conspire Would not we shatter it to bits -- and then !@#$%Re-mould it nearer to the Heart's Desire! ah love! could you and i with fate conspire !@#$%Would not we shatter it to bits -- and then !@#$%would not we shatter it to bits -- and then !@#$%To grasp this sorry Scheme of Things entire, to grasp this sorry scheme of things entire, !@#$%Ah Love! could you and I with Fate conspire Re-mould it nearer to the Heart's Desire! Ah Love! could you and I with Fate conspire To grasp this sorry Scheme of Things entire, !@#$%re-mould it nearer to the heart's desire! re-mould it nearer to the heart's desire! $
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