PHP Program to Check Leap Year

A leap year is a calendar year in which an additional day is added to February month. In a leap year, the number of days in February month and the year are 29 and 366 respectively. A year that is not a leap year is called a common year. A year is said to be a leap year if:

• it is divisible by 4.
• it is divisible by 4 but not divisible by 100.
• it is divisible by 4, 100 and 400.

Method 1: Using conditional statements

In the example below, conditional statements are used to identify a leap year.

<?php
$year = 2019;
if ($year % 400 == 0) {
   echo $year." is a leap year.";
} elseif ($year % 100 == 0) {
   echo $year." is not a leap year.";
} elseif ($year % 4 == 0) {
   echo $year." is a leap year.";
} else {
   echo $year." is not a leap year.";
}
?>

The above code will give the following output:

2019 is not a leap year.

Method 2: Using function

In the example below, a function called leapyear() is created which takes year as argument and prints whether the passed year is a leap year or not.

<?php
function leapyear($year) {
  if ($year % 400 == 0) {
     echo $year." is a leap year.";
  } elseif ($year % 100 == 0) {
     echo $year." is not a leap year.";
  } elseif ($year % 4 == 0) {
     echo $year." is a leap year.";
  } else {
     echo $year." is not a leap year.";
  }
}

leapyear(2019);
?>

The above code will give the following output:

2019 is not a leap year.