Topic: PHP Basics – Part 3 of 10: Control Structures (if, else, elseif, switch, loops)

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1. Conditional Statements in PHP

PHP allows decision-making in your code through control structures like if, else, elseif, and switch.

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2. `if`, `else`, and `elseif` Statements

<?php
$score = 85;

if ($score >= 90) {
    echo "Grade: A";
} elseif ($score >= 80) {
    echo "Grade: B";
} elseif ($score >= 70) {
    echo "Grade: C";
} else {
    echo "Grade: F";
}
?>

• The condition inside if() must return true or false.

• You can chain multiple conditions using elseif.

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3. `switch` Statement

• Good for checking a variable against multiple possible values.

<?php
$day = "Tuesday";

switch ($day) {
    case "Monday":
        echo "Start of the week!";
        break;
    case "Friday":
        echo "Weekend is near!";
        break;
    case "Sunday":
        echo "Rest day!";
        break;
    default:
        echo "Just another day.";
}
?>

• Each case must end with a break to avoid fall-through.

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4. Loops in PHP

Loops allow repeating code multiple times.

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5. `while` Loop

<?php
$i = 0;
while ($i < 5) {
    echo "Number: $i<br>";
    $i++;
}
?>

• Repeats while the condition is true.

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6. `do...while` Loop

<?php
$i = 0;
do {
    echo "Count: $i<br>";
    $i++;
} while ($i < 3);
?>

• Executes at least once even if the condition is false initially.

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7. `for` Loop

<?php
for ($i = 1; $i <= 5; $i++) {
    echo "Line $i<br>";
}
?>

• Most commonly used loop with initializer, condition, and increment.

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8. `foreach` Loop

• Used to iterate over arrays.

<?php
$colors = array("red", "green", "blue");
foreach ($colors as $color) {
    echo "Color: $color<br>";
}
?>

• Also works with key-value pairs:

<?php
$person = array("name" => "Ali", "age" => 28);
foreach ($person as $key => $value) {
    echo "$key: $value<br>";
}
?>

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9. Control Keywords

• break – Exit a loop or switch.
• continue – Skip current iteration and go to the next.

for ($i = 1; $i <= 5; $i++) {
    if ($i == 3) continue;
    echo "$i<br>";
}

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10. Summary

• Conditional logic (if, else, switch) helps make decisions.

• Loops (for, while, foreach) help automate repetitive tasks.

• Control flow is critical for building dynamic applications.

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Exercise

• Write a PHP script that prints numbers 1 to 20, but skips multiples of 3 using continue, and stops completely if the number is 17 using break.

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#PHP #ControlStructures #Loops #PHPTutorial #BackendDevelopment

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