Here's a simple example that demonstrates the if, elseif, and else statements, as well as the ? (ternary) operator.
<?php $hour = date( "G" ); $year = date( "Y" ); if ( $hour >= 5 && $hour < 12 ) { echo "Good morning!"; } elseif ( $hour >= 12 && $hour < 18 ) { echo "Good afternoon!"; } elseif ( $hour >= 18 && $hour < 22 ) { echo "Good evening!"; } else {/*from www . j a v a2s . c om*/ echo "Good night!"; } $leapYear = false; if ( ( ( $year % 4 == 0 ) && ( $year % 100 != 0 ) ) || ( $year % 400 == 0 ) ) $leapYear = true; echo "$year is" . ( $leapYear ? "" : " not" ) . " a leap year?"; ?>
The script sets two variables: $hour, holding the current hour of the day.
$year holds the current year.
It uses PHP's date() function to get these two values: passing the string "G" to date() returns the hour in 24-hour clock format, and passing "Y" returns the year.
Next, the script uses an if...elseif...else construct to display an appropriate greeting.
If the current hour is between 5 and 12 the script displays "Good morning!";
if it's between 12 and 18 it displays "Good afternoon!" and so on.
Finally, the script works out if the current year is a leap year.
It creates a new $leapYear variable, set to false by default, then sets $leapYear to true if the current year is divisible by 4 but not by 100, or if it's divisible by 400.