C言語のきほん「現在の日付と時刻を協定世界時で表示しよう」

//現在の日付・時刻を表示（UTC:協定世界時）

#include <time.h>
#include <stdio.h>

//日付・時刻を表示する関数
void put_date(const struct tm *timer)
{
    char *wday_name[] = {"日","月","火","水","木","金","土"};

    printf("%4d年%02d月%02d日(%s)%02d時%02d分%02d秒",
            timer->tm_year + 1900,
            timer->tm_mon + 1,
            timer->tm_mday,
            wday_name[timer->tm_wday],
            timer->tm_hour,
            timer->tm_min,
            timer->tm_sec
            );
}

int main(void)
{
    time_t current;
    struct tm *timer;

    time(¤t);
    timer = gmtime(¤t);

    printf("現在の日付・時刻はUTCで");
    put_date(timer);
    printf("です\n");

    return 0;
}