时间转换 [英] Time Conversion
问题描述
我有2个时间值：
系统时间和用户输入。
1）系统时间是从1970年1月1日起的秒数按
计算
time_t秒;
SYSTEMTIME stime;
time（& secs）;
2）用户的输入格式为hr：min：sec，这是一个字符串
值。
但是已经获得了单独的值使用
sscanf（storedTimeValue，"％d：％d：％d"，& hour，& minutes，& seconds）;
所以现在我有3个小时，分钟和秒的整数值。
3）我有一个函数来计算2
时间值之间的时差，
但是这两个时间值都需要从1970年1月1日开始。
有没有办法，我可以将给定时间的用户转换成时间
从1970年1月1日开始，
这样我就可以得到系统时间与用户之间的差额
给定时间。
I have 2 time values:
System time and an input from the user.
1) System time is in the form of seconds from 1/1/1970 calculated by
using
time_t secs;
SYSTEMTIME stime;
time(&secs);
2) The input from the user is in form hr:min:sec which is a string
value.
But the seperate values have been obtained by using
sscanf(storedTimeValue, "%d:%d:%d", &hour,&minutes,&seconds);
So now I have 3 integer values for hour,minutes and seconds.
3) I have a function which calculates the time difference between 2
time values,
but both these time values need to be seconds from 1/1/1970.
Is there any way by which,I could convert the user given time into time
in seconds from 1/1/1970,
so that I can get the difference between the system time and the user
given time.
推荐答案
" moni" < mo ******* @ gmail.comwrote：
"moni" <mo*******@gmail.comwrote:
我有2个时间值：系统时间和用户输入。
I have 2 time values: System time and an input from the user.
1）系统时间是从1970年1月1日起的秒数形式
1) System time is in the form of seconds from 1/1/1970
ISO C并不能保证。它也没有给你任何方式做数学
on time_t。但一切都没有丢失......
ISO C doesn''t guarantee that. Nor does it give you any way to do maths
on time_t. But all is not lost...
time_t secs;
SYSTEMTIME stime;
time_t secs;
SYSTEMTIME stime;
这种类型在C中不存在。它也没有必要。
This type doesn''t exist in C. It''s also not necessary.
时间（安培;秒）;
time(&secs);
2）用户的输入格式为hr：min：sec，这是一个字符串
值。但是通过使用
2) The input from the user is in form hr:min:sec which is a string
value. But the seperate values have been obtained by using
sscanf（storedTimeValue，"％d：％d：％d"，& hour，&）获得了单独的值。 ;分钟，&安培;秒）;
sscanf(storedTimeValue, "%d:%d:%d", &hour,&minutes,&seconds);
所以现在我有3个小时，分钟和秒的整数值。
So now I have 3 integer values for hour,minutes and seconds.
好。请注意，您仍然需要相关日期，但是从时间（）得到的时间可以得到
。
Good. Note that you''ll still need the relevant date, but that can be had
from the time_t you got from time().
3）我有一个函数来计算2
时间值之间的时差，但这两个时间值都需要是1970年1月1日的秒数。
3) I have a function which calculates the time difference between 2
time values, but both these time values need to be seconds from 1/1/1970.
然后你的功能错了。用于计算两个time_t'之间的
差异的正确函数在< time.h>中，并且它被称为
difftime（）。无论time_t的格式如何，这都必须有效，并且因此优于自制函数，该函数假定为1970年1月1日的
和分辨率1秒。
Then you have the wrong function. The right function to calculate the
difference between two time_t''s is in <time.h>, and it''s called
difftime(). This must work regardless of the format of a time_t, and is
therefore superior to a home-made function which assumes an epoch of
1970/01/01 and a resolution of 1 second.
有没有办法，我可以将给定时间的用户转换成时间
，以秒为单位，从1/1开始/ 1970，
Is there any way by which,I could convert the user given time into time
in seconds from 1/1/1970,
否。但是，有一种方法可以将它转换为time_t。它有点好处，但是它可以在任何地方使用。
首先你将time_t转换为struct tm，使用gmtime（）或
localtime（）。接下来，将此
struct tm的tm_hour，tm_min和tm_sec成员设置为从sscanf（）获得的值。然后使用mktime（）将此
struct tm转换回第二个time_t。最后你使用difftime（）减去时间_t'和
，而鲍勃是你的叔叔。所有这些
函数都是ISO标准C，所有（显然除了sscanf（）除外）可以在< time.h>中找到
。
Richard
No. However, there _is_ a way to convert it into a time_t. It''s a bit
roundabout, but it does work anywhere.
First you convert your time_t into a struct tm, using either gmtime() or
localtime(). Next you set the tm_hour, tm_min and tm_sec members of this
struct tm to the values you got from sscanf(). Then you convert this
struct tm back to a second time_t, using mktime(). Finally you subtract
both time_t''s using difftime(), and Bob''s your uncle. All of these
functions are ISO Standard C, and all (except sscanf(), obviously) can
be found in <time.h>.
Richard
Richard Bos说：
< snip>
Richard Bos said:
<snip>
ISO C并没有给你任何方式在time_t上做数学。
ISO C doesn''t [...] give you any way to do maths on time_t.
....除了difftime。
-
Richard Heathfield
Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk
电子邮件：rjh在上面的域名（但显然放弃了www）
....except for difftime.
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)
struct tm * newtime，* oldtime;
time_t结果;
time_t long_time;
double elapsed_time;
sscanf（stringtoconvert，"％d：％d：％d"，& hour，& minutes，& seconds）;
time（& long_time）; / *获取时间长整数。 * /
newtime = localtime（& long_time）; / *转换为当地时间。 * /
oldtime = localtime（& long_time）;
newtime-> tm_isdst = 0;
newtime-> tm_hour =小时;
newtime-> tm_min =分钟;
newtime-> tm_sec =秒;
/ / newtime-> tm_year = 2006;
result = mktime（& newtime）;
elapsed_time = difftime（结果，long_time） ;
printf（时间是％d，％d，结果，long_time）;
这里结果总是为-1，即。 mktime总是返回-1。
你能告诉我原因吗？
Thanx很多..
Richard Heathfield写道：
struct tm *newtime, *oldtime;
time_t result;
time_t long_time;
double elapsed_time;
sscanf(stringtoconvert, "%d:%d:%d", &hour,&minutes,&seconds);
time( &long_time ); /* Get time as long integer. */
newtime = localtime( &long_time ); /* Convert to local time. */
oldtime = localtime( &long_time );
newtime->tm_isdst = 0;
newtime->tm_hour = hour;
newtime->tm_min = minutes;
newtime->tm_sec = seconds;
//newtime->tm_year = 2006;
result = mktime(&newtime);
elapsed_time = difftime( result, long_time );
printf("time is %d, %d", result, long_time);
Here the result always come s to -1, ie. mktime is always returning -1.
Can you tell me the reason?
Thanx alot..
Richard Heathfield wrote:
Richard Bos说：
< snip>
Richard Bos said:
<snip>
ISO C并没有给你任何方式在time_t上做数学。
ISO C doesn''t [...] give you any way to do maths on time_t.
...除了difftime。
-
Richard Heathfield
Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk
电子邮件：rjh在上面的域名（但显然放弃了www）
...except for difftime.
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)
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