How to get time_t value that is a week old

Hi there,
How to get a time_t (Unix Time) value that is a week old, month old, day old.

I am getting the current time as below.

time_t current_time;
time(&current_time);
cout << "Current Time: " << current_time << endl;

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ambuliAsked:
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ozoCommented:
current_time-7*24*60*60
current_time-30*24*60*60
current_time-24*60*60
If you need the exactly corresponding time of day across daylight saving changes, or the corresponding day of the month across month length changes, this may need to be modified
ambuliAuthor Commented:
Thanks.  I was thinking of doing the same.  But, is there a better way to do this?
ozoCommented:
Does "better" mean accounting for daylight saving changes and/or month length changes?
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ambuliAuthor Commented:
yes :-)
evilrixSenior Software Engineer (Avast)Commented:
Why not create a TM struct with the time/date now and then subtract the number of days/months?
http://www.cplusplus.com/reference/ctime/tm/

Once you've done that you can turn it into a time_t using mktime
http://www.cplusplus.com/reference/ctime/mktime/

Alternatively, if you are using C++11 you can use the new Chrono library.
http://www.cplusplus.com/reference/chrono/
ozoCommented:
struct tm t[1];
localtime_r(&current_time, t);

t[0].tm_mday-=7;
time_t weekOld=mktime(&t[0]);
cout << weekOld << endl;
t[0].tm_mday+=7;

t[0].tm_mon-=1;
time_t monthOld=mktime(&t[0]);
cout << monthOld << endl;
t[0].tm_mon+=1;

t[0].tm_mday-=1;
time_t dayOld=mktime(&t[0]);
cout << dayOld << endl;
t[0].tm_mday+=1;

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