How to determine whether a year is a leap year in PHP?

The condition to determine whether it is a leap year is to meet one of the following two conditions: the year number can be evenly divisible by 4, but not 100; second, the year number can be evenly divisible by 4, but also divisible by 400. So how does PHP determine whether a year is a leap year? The following article will introduce to you how to use PHP to determine whether a year is a leap year. I hope it will be helpful to you.

1, PHP leap year calculation method 1:

①. Ordinary years can be divisible by 4 but not 100 Divisible by leap years. (For example, 2004 is a leap year, and 1900 is not a leap year)

②. A leap year is a century year that is divisible by 400 but not divisible by 3200. (For example, the year 2000 is a leap year, and the year 3200 is not a leap year)

<?php
header("content-type:text/html;charset=utf-8");
$year=mt_rand(1900,2200);//从1900年到2200，可以自己改，也可以给一个定值。
if($year%100==0){//判断世纪年
if ($year%400==0&&$year%3200!=0){
   echo "世纪年".$year."是闰年!";//世纪年里的闰年
}
else{echo "世纪年".$year."不是闰年!";}
}
else{//剩下的就是普通年了
   if($year%4==0&&$year%100!=0){
   echo "普通年".$year."是闰年!";//普通年里的闰年
}
else {echo "普通年".$year."不是闰年!";}
}
?>

2. Method 2 of judging leap year in php:

<?php
header("content-type:text/html;charset=utf-8");
$year = 2008;//可以像上例一样用mt_rand随机取一个年，也可以随便赋值。
$time = mktime(20,20,20,4,20,$year);//取得一个日期的 Unix 时间戳;
if (date("L",$time)==1){ //格式化时间，并且判断是不是闰年，后面的等于一也可以省略；
echo $year."是闰年";
}else{
echo $year."不是闰年";
}
?>

Method 3 of php judging leap year and calculating leap year:

<?php
header("content-type:text/html;charset=utf-8");
$year = 2000;
$time = mktime(20,20,20,2,1,$year);//取得一个日期的 Unix 时间戳;
if (date("t",$time)==29){ //格式化时间，并且判断2月是否是29天；
echo $year."是闰年";//是29天就输出时闰年；
}else{
echo $year."不是闰年";
}
?>

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