Every other week date

curtranhome · Joined: 04 Jun 2008 Posts: 77

is there any way to display the date 2 weeks in advance? like today is the 17th, can we display the date on the 1st of december? and the the 15th, then the 29th, etc. without having to manually update it?

kanenas · Joined: 14 Dec 2004 Posts: 341

It depends entirely how you're generating the date. Any scripting language that supports dates should have a way of specifying offsets for dates & times, so you can generate a date a given distance into the future or past.

curtranhome · Joined: 04 Jun 2008 Posts: 77

ok well thanks, but i'm more of a newbie when it comes to server side scripting, in other words, how do i do something like that?

kanenas · Joined: 14 Dec 2004 Posts: 341

You should always describe the relevant portions of the environment. What scripting languages do you have available (including versions)? For example, in PHP you can generate a timestamp two weeks into the future with either:

curtranhome · Joined: 04 Jun 2008 Posts: 77

I'm not sure on the complete list of available languages, but, so far, i do know that i can run anything but mySQL. not meaning to be a problem, but is there a way to set a certain date and have the script build off of that, like say i set a date to today (12/12/09) then i insert a code that generates the date 2 weeks from that date, then display, then when that day comes, it will set it as the date to add another 2 weeks. is there a way to do anything like that? sorry if its hard to understand Crying or Very sad

Thanks ahead of time
~curtranhome

kanenas · Joined: 14 Dec 2004 Posts: 341

There are two approaches: store the next date somewhere (preferably a database), updating it when the date arrives, or calculate the difference between the current date and a reference date and use a round-to-nearest, floor, ceiling or truncation. I'll call all of these "rounding functions".

Let's examine the second option. Here's the breakdown.

We want our calculation relative to a specific date, so we start by subtracting this base date, and add it back at the end
Rounding x to a multiple of n is done by: "round(x / n) * n". Substituting floor, ceiling or truncation for "round" in this formula will perform that appropriate function on x to the nearest n.
We want the next fortnight, and timestamps are expressed in seconds, so we're rounding to 60*60*24*14 seconds (the number of seconds in a fortnight).
Ceiling (which gives the nearest later fortnight) may seem the natural rounding function to get the next fortnight, but it gives the wrong value when a date is on the fortnight. Instead, find the floor (the nearest earlier fortnight) and add one. You could also calculate the nearest earlier fortnight and add a fortnight. The two are equivalent, due to the distributive property:

Code:

floor(x/n + 1) * n = (floor(x/n) + 1) * n = floor(x/n)*n + n

Use whichever makes more sense to you.

This leads to:

curtranhome · Joined: 04 Jun 2008 Posts: 77

Ok thanks, and not to be a pest or anything but how is this supposed to be put together? cause after the function, the echo makes the code useless.

Thanks,
curt

kanenas · Joined: 14 Dec 2004 Posts: 341

I'm not sure I follow. If you don't want to echo the date, don't echo it. Even the function fortnightly is merely an example. Adapt it as necessary for your requirements (which you apparently haven't stated fully, so I can't address).

curtranhome · Joined: 04 Jun 2008 Posts: 77

Ok well, when I insert and upload the file with only the function, it works, but when I add the echo to the absolute end of the php script, it dumps the entire page. So I want to know how the script is put together (noteing that you have them in seperate code area)

kanenas · Joined: 14 Dec 2004 Posts: 341

What do you mean by "dumps the entire page"?

I had them separate because fortnightly was a particular implementation and the echo statement was a usage example. You'd integrate it into your page however you wish (generally speaking, group functions by related tasks into scripts, then include the scripts and call the functions in the pages). I have no idea how your pages are coded, thus have no idea how to add fortnightly into your pages. This is why I included an example of how to use the fortnightly function.