The code will output "Have a nice weekend!" if the current day is Friday, otherwise - "Have a nice day!"

$d = date("D");
if($d == "Fri"){
    echo "Have a nice weekend!";
} else{
    echo "Have a nice day!";
}
echo "\n";

Output "Have a good day!" if the current time is less than 20, and "Have a good night!" otherwise:

$t = date("H");
if ($t < "20") {
    echo "Have a good day!";
} else {
    echo "Have a good night!";
}

If

$age

is more than

18

, prints

Adult

otherwise prints

Child

$age = 20;
if ($age > 18) {
    echo 'Adult';	
} else {
    echo 'Child';	
}