Conditional statements are used to perform different actions based on different conditions.
Very often when you write code, you want to perform different actions for different conditions. You can use conditional statements in your code to do this.
In PHP we have the following conditional statements:
if statement - executes some code if one condition is true
if...else statement - executes some code if a condition is true and another code if that condition is false
if...elseif...else statement - executes different codes for more than two conditions
switch statement - selects one of many blocks of code to be executed
The if statement executes some code if one condition is true.
if (condition) {
code to be executed if condition is true;
}
Output "Have a good day!" if the current time (HOUR) is less than 20:
<?php
$t = date("H");
if ($t < "20") {
echo "Have a good day!";
}
?>
The if...else statement executes some code if a condition is true and another code if that condition is false.
if (condition) {
code to be executed if condition is true;
} else {
code to be executed if condition is false;
}
Output "Have a good day!" if the current time is less than 20, and "Have a good night!" otherwise:
<?php
$t = date("H");
if ($t < "20") {
echo "Have a good day!";
} else {
echo "Have a good night!";
}
?>
The if...elseif...else statement executes different codes for more than two conditions.
if (condition) {
code to be executed if this condition is true;
} elseif (condition) {
code to be executed if first condition is false and this condition is true;
} else {
code to be executed if all conditions are false;
}
Output "Have a good morning!" if the current time is less than 10, and "Have a good day!" if the current time is less than 20. Otherwise it will output "Have a good night!":
<?php
$t = date("H");
if ($t < "10") {
echo "Have a good morning!";
} elseif ($t < "20") {
echo "Have a good day!";
} else {
echo "Have a good night!";
}
?>
Output "Hello World" if $a is greater than $b.
Output "Hello World" if $a is NOT equal to $b.
Output "Yes" if $a is equal to $b, otherwise output "No".
Output "1" if $a is equal to $b, print "2" if $a is greater than $b, otherwise output "3".
-----------------------------------------
score 0-49 Output "Grade 0"
score 50-54 Output "Grade 1",
score 55-59 Output "Grade 1.5",
score 60-64 Output "Grade 2",
score 65-69 Output "Grade 2.5",
score 70-74 Output "Grade 3",
score 75-79 Output "Grade 3.5"
score 80-100 Output "Grade 4"
otherwise output "EEROR SCORE"