Determining if a year is a leap year

[ballygowanboy]

right, i've to write a small script to check if a year is leapyear or not. i understand that

a) the year or number when divided by 400, 100 and 4, should leave me with a module remainder of 0, correct?

so, if what i've said above is right.......... i wrote this script...... now i'm sure this is probably completly wrong, but i'm a bit new to all this.....

the script is being parsed to a html for by the way.........

<?php
 
 
$leap = $x;
 
 
 
$x = $_POST["year"];
 
if ($leap == (($x%100) == 0 || ($x%400) == 0 || ($x%4) == 0)
 
{
echo("this is a leap year");
}
 
 
else
{
 
echo("this is not a leap year");
}
 
?>

i'm getting an error on line 12, which is just a curley brace, {

am i close here, of way off?

ta

[mwasif]

You are missing ending ')' in if
[PHP]if ($leap == (($x%100) == 0 || ($x%400) == 0 || ($x%4) == 0))[/PHP]
Use this to know if the year is leap or not
[PHP]$year = 2005;
if(date("L", mktime(1, 0, 0, 1, 1, $year)) == 1)
echo "this is a leap year";
else
echo "this is not a leap year";[/PHP]
If you have PECL then you can use mcal_is_leap_year().

[ballygowanboy]

You are missing ending ')' in if
[PHP]if ($leap == (($x%100) == 0 || ($x%400) == 0 || ($x%4) == 0))[/PHP]
Use this to know if the year is leap or not
[PHP]$year = 2005;
if(date("L", mktime(1, 0, 0, 1, 1, $year)) == 1)
echo "this is a leap year";
else
echo "this is not a leap year";[/PHP]
If you have PECL then you can use mcal_is_leap_year().

thanks, yes, was missing a )

i don't really understand the code you wrote, would you be able to comment on my code?

the user has to put a year, just a number in a text box, and submit.

at the moment i'm only learning about Conditionals.

does my code make any sence?

[ballygowanboy]

ok, i figured this out, the code.

<?php
 
$x = $_POST["year"];
 
 
$leap = $x;
 
 
if ( ( ($x % 4 == 0) && ($x % 100 !=0) )  ||  ($x % 400 == 0) )
 
{
        echo("this is a leap year");
}
 
 
else 
{ 
 
        echo("this is not a leap year");
}
 
?>

[kovik]

Why would you need that much logic to determine a leap year? Every four years is a leap year. Period.

FYI, PHP has date and time functions that can give you leap years and the like.

[pbmods]

Hey, go easy on him. He's doing homework. When does homework ever have to be practical?

date('L') does the same thing, but what would ballygowanboy learn from that?

[kovik]

Hey, go easy on him. He's doing homework. When does homework ever have to be practical?

date('L') does the same thing, but what would ballygowanboy learn from that?

Hehe, I was just implying that x%4 is all he needs, and the rest is unnecessary. In fact, the logic says that every four years is a leap year except for every 100 years, unless it is every 400 years? So, only one of those would be a leap year per 4 centuries? It doesn't really make sense.

[nathj]

<?php
 
$x = $_POST["year"];
 
 
$leap = $x;
 
?>

why define $x and $leap the same and only use one of them? Perhaps it would be better, and this has no bearing on the lopo issue at all, if you only had one variable - $leap. Define this directly from the $_POST['year'] and save some processing cycles.

Just thought I'd add my 2cents worth
nathj

[pbmods]

Changed thread title to better describe the problem.

[ken205726]

Quote: "In fact, the logic says that every four years is a leap year except for every 100 years, unless it is every 400 years? So, only one of those would be a leap year per 4 centuries? It doesn't really make sense."

That actually is the rule to keep the seasons from slowly drifting.

1900 was not a leap year
2000 WAS a leap year
2100 will not be a leap year

Of course not too many PHP programmers need to worry. The UNIX timestamp function will roll its 32 bits in about 2027, I think, so a lot programs will fall over.

A nice little earner for the clean up crews.

[kovik]

That actually is the rule to keep the seasons from slowly drifting.

Seriously? That's kinda cool. I didn't know that.

Of course not too many PHP programmers need to worry. The UNIX timestamp function will roll its 32 bits in about 2027, I think, so a lot programs will fall over.

A nice little earner for the clean up crews.

Well, we'll come up with a alternative to timestamps by then, and it'll be forced into the date() function in PHP 9. ;)

[ballygowanboy]

why define $x and $leap the same and only use one of them? Perhaps it would be better, and this has no bearing on the lopo issue at all, if you only had one variable - $leap. Define this directly from the $_POST['year'] and save some processing cycles.

Just thought I'd add my 2cents worth
nathj

you're right, took that out, was left over code from a couple of attempts.

[ballygowanboy]

Why would you need that much logic to determine a leap year? Every four years is a leap year. Period.

FYI, PHP has date and time functions that can give you leap years and the like.

Every fourth year is a leap year - 1996, 2004 and 2008 except

Years ending in 00 are not leap - 1900, 1800, 1700 are not leap years but

Every 400 years there is a leap year ending in 00 (1600 and 2000 are leap years)


also, i'm only learning, so need to understand the basic principals of programming.

[nathj]

also, i'm only learning, so need to understand the basic principals of programming.

That's a great idea - get the basics in place and the rest will follow.

A good understanding of the basics will make you a better programmer in the long run.

nathj

[kovik]

That's a great idea - get the basics in place and the rest will follow.

A good understanding of the basics will make you a better programmer in the long run.

nathj

Yeah. It seems like everyone else just jumps in trying to make YouTube or Facebook from scratch. :-p

[pbmods]

I think this question has been sufficiently answered. I'm closing this thread.