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Control Statements in php

Ayesha
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Control statements allow you to make decisions in your code. php supports if, else, elseif, switch, and the modern match expression.

Video Explanation​

The if Statement​

Executes code if a condition is true:

<?php
$age = 20;

if ($age >= 18) {
    echo "You are an adult.";
}
?>

The if...else Statement​

Executes one block if true, another if false:

<?php
$score = 55;

if ($score >= 60) {
    echo "Pass";
} else {
    echo "Fail";
}
?>

The if...elseif...else Statement​

Tests multiple conditions in sequence:

<?php
$marks = 75;

if ($marks >= 90) {
    echo "Grade: A";
} elseif ($marks >= 75) {
    echo "Grade: B";
} elseif ($marks >= 60) {
    echo "Grade: C";
} else {
    echo "Grade: F";
}
// Output: Grade: B
?>

Shorthand if (Ternary)​

<?php
$isLoggedIn = true;
echo $isLoggedIn ? "Welcome back!" : "Please log in.";
?>

The switch Statement​

Tests a variable against multiple values:

<?php
$day = "Monday";

switch ($day) {
    case "Monday":
        echo "Start of the work week.";
        break;
    case "Friday":
        echo "End of the work week!";
        break;
    case "Saturday":
    case "Sunday":
        echo "It's the weekend!";
        break;
    default:
        echo "Midweek day.";
}
?>

Note: Always use break to prevent fall-through to the next case.

The match Expression (php 8+)​

A cleaner alternative to switch with strict comparison:

<?php
$status = 2;

$message = match($status) {
    1 => "Active",
    2 => "Inactive",
    3 => "Banned",
    default => "Unknown"
};

echo $message; // Inactive
?>

Differences: switch vs match​

Featureswitchmatch
ComparisonLoose (==)Strict (===)
Fall-throughYes (needs break)No
Returns valueNoYes
Multiple conditionsYes (stacked cases)Yes (comma-separated)

Nested if Statements​

<?php
$age = 25;
$hasLicense = true;

if ($age >= 18) {
    if ($hasLicense) {
        echo "You can drive.";
    } else {
        echo "You need a license.";
    }
} else {
    echo "You are too young to drive.";
}
?>

Alternative Syntax​

php allows an alternative syntax for control structures, useful in HTML templates:

<?php $loggedIn = true; ?>

<?php if ($loggedIn): ?>
    <p>Welcome, user!</p>
<?php else: ?>
    <p>Please log in.</p>
<?php endif; ?>

Note: This alternative syntax using : and endif; / endswitch; is especially useful when mixing php with HTML markup.

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