オペレーティングシステム
write1.c
#include fcntl.h
#include stdio.h
#include time.h
int main()
{
int fd;
char s[50];
time_t t;
int i, j, n = 1, maxprime = 3;
int max = 100000;
/*** time stamp1 here ***/
t = time(NULL);
printf("Start time: %s", ctime(&t));
fd = open("file1", O_CREAT | O_TRUNC | O_WRONLY, 0664);
while (1)
{
printf(" ");
fgets(s, 50, stdin);
// get string
if (s[0] == '\n')
break;
/*** Big processing here ***/
for (i = 3; i <= max; i = i + 2)
{
for (j = 3; (i - (i / j) * j) != 0; j++);
if (i == j)
{
n++;
maxprime = i;
}
}
write(fd, s, sizeof(s));//write string to file
}
/*** time stamp2 here ***/
t = time(NULL);
printf("End time: %s", ctime(&t));
close(fd);
}
結果
[s033449@kanagawa-info s033449]$ ./a.out
Start time: Thu Jun 23 15:09:48 2005
keiichi
oshiba
kazuyo
sekio
kazuhito
naoya
saki
aa
abc
ewing
End time: Thu Jun 23 15:12:43 2005
[s033449@kanagawa-info s033449]$ gcc read1.c
[s033449@kanagawa-info s033449]$ ./a.out
keiichi
oshiba
kazuyo
sekio
kazuhito
naoya
saki
aa
abc
ewing
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