【課題４−３】
（プログラム例１）
#include <stdio.h>
#include <string.h>
#define N 12
int main(void) {
char
*month[N]={"January", "February", "March",
"April",
"May",
"June", "July", "August",
"September",
"October", "November", "December"};
int
i;
for
(i = 0; i < N; i++) {
printf("length
of \"%s\": %d\n", month[i], strlen(month[i]));
}
return
0;
}
（実行結果）
length of "January": 7
length of "February": 8
length of "March": 5
length of "April": 5
length of "May": 3
length of "June": 4
length of "July": 4
length of "August": 6
length of "September": 9
length of "October": 7
length of "November": 8
length of "December": 8
（プログラム例２）
#include <stdio.h>
#include <string.h>
#define N 12
void sort1(char *dat[]);
void sort2(char *dat[]);
int main(void) {
char
*month[N]={"January", "February", "March",
"April",
"May",
"June", "July", "August",
"September",
"October", "November", "December"};
int
i;
sort1(month); //辞書順でのソート
sort2(month); //文字数でのソート
for
(i = 0; i < N; i++) {
printf("%s\n",
month[i]);
}
return
0;
}
/* 基本挿入法で文字列を辞書順にソートする関数 */
void sort1(char *dat[]) {
int
i, j;
char
*temp;
for
(i = 0; i < N; i++) {
for
(j = i-1; j >= 0; j--) {
if
(strcmp(dat[j], dat[j+1]) > 0) {
temp
= dat[j];
dat[j]
= dat[j+1];
dat[j+1]
= temp;
}
else
break;
}
}
}
/* 基本挿入法で文字列を長さ順にソートする関数 */
void sort2(char *dat[]) {
int
i, j;
char
*temp;
for
(i = 0; i < N; i++) {
for
(j = i-1; j >= 0; j--) {
if
(strlen(dat[j]) > strlen(dat[j+1])) {
temp
= dat[j];
dat[j]
= dat[j+1];
dat[j+1]
= temp;
}
else
break;
}
}
}
（実行結果）
May
July
June
April
March
August
January
October
December
February
November
September
（プログラム例３）標準ライブラリ関数qsortを用いた例
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 12
int cmpstr(const void *, const
void *);
int cmplen(const void *, const
void *);
int main(void) {
char
*month[N]={"January", "February", "March",
"April",
"May",
"June", "July", "August",
"September",
"October", "November", "December"};
int
i;
qsort(month,
N, sizeof(char *), cmpstr); //辞書順でのソート
qsort(month,
N, sizeof(char *), cmplen); //文字数でのソート
for
(i = 0; i < N; i++) {
printf("%s\n",
month[i]);
}
return
0;
}
/* ２つの文字列の辞書順を比較する関数 */
int cmpstr(const void *s1, const
void *s2) {
return
strcmp(*(char **)s1, *(char **)s2);
}
/* ２つの文字列の長さを比較する関数 */
int cmplen(const void *s1, const
void *s2) {
return
strlen(*(char **)s1)-strlen(*(char **)s2);
}
（実行結果）
May
July
June
April
March
August
January
October
December
February
November
September