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Lesson 12 of 50 – PHP Switch Statement
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PHP Switch Statement

The switch statement is used to execute different blocks of code depending on the value of an expression. It is useful when you need to compare one value against several possible cases.

1. What Is the Switch Statement?

A switch statement checks an expression against different case values. When a matching case is found, its code executes.

Syntax:

switch ($variable) {
    case value1:
        // Code for value1
        break;

    case value2:
        // Code for value2
        break;

    default:
        // Code when no case matches
}

The break statement stops execution from continuing into the following cases.

2. Basic Switch Example

Let us display a message based on a day number. 

<?php
$day = 3;

switch ($day) {
    case 1:
        echo "Monday";
        break;

    case 2:
        echo "Tuesday";
        break;

    case 3:
        echo "Wednesday";
        break;

    default:
        echo "Invalid day";
}
?>

Output:

Wednesday

Because $day is 3, PHP executes the third case and stops at break.

3. Understanding the break Statement

The break statement exits the switch after the matching case has executed. 

<?php
$number = 1;

switch ($number) {
    case 1:
        echo "One ";
        break;

    case 2:
        echo "Two ";
        break;

    case 3:
        echo "Three ";
        break;
}
?>

Output:

One

PHP executes the code for case 1 and exits the switch because of break.

If you omit break, PHP can continue executing subsequent case blocks until it reaches a break or the end of the switch. This behavior is called fall-through.

4. Using the default Case

The default case runs when no case matches the switch expression. 

<?php
$color = "Purple";

switch ($color) {
    case "Red":
        echo "Color is Red";
        break;

    case "Blue":
        echo "Color is Blue";
        break;

    case "Green":
        echo "Color is Green";
        break;

    default:
        echo "Color not found";
}
?>

Output:

Color not found

Since none of the listed cases matches "Purple", the default block executes.

5. Grouping Multiple Cases

Multiple cases can share the same block of code. This is useful when different values should produce the same result. 

<?php
$day = "Sunday";

switch ($day) {
    case "Saturday":
    case "Sunday":
        echo "Weekend";
        break;

    default:
        echo "Working day";
}
?>

Output:

Weekend

Both Saturday and Sunday lead to the same message because neither case has a statement before the shared block.

6. Switch with a Grade Calculator

A switch statement can also work with a calculated or previously assigned value. 

<?php
$grade = "B";

switch ($grade) {
    case "A":
        echo "Excellent";
        break;

    case "B":
        echo "Very Good";
        break;

    case "C":
        echo "Good";
        break;

    case "D":
        echo "Needs Improvement";
        break;

    default:
        echo "Invalid grade";
}
?>

Output:

Very Good

The value of $grade matches case B, so PHP displays "Very Good".

7. Simple Calculator Using Switch

You can create a simple calculator by checking which arithmetic operator the user has selected. 

<?php
$a = 20;
$b = 5;
$operator = "*";

switch ($operator) {
    case "+":
        echo $a + $b;
        break;

    case "-":
        echo $a - $b;
        break;

    case "*":
        echo $a * $b;
        break;

    case "/":
        if ($b != 0) {
            echo $a / $b;
        } else {
            echo "Cannot divide by zero";
        }
        break;

    default:
        echo "Invalid operator";
}
?>

Output:

100

Since the operator is *, PHP multiplies the two numbers.

In real applications, validate user input and handle division by zero before performing division.

8. Switch with String Values

Switch is useful for selecting an action based on a string value, such as a menu choice. 

<?php
$choice = "about";

switch ($choice) {
    case "home":
        echo "Welcome to the Home Page";
        break;

    case "about":
        echo "Welcome to the About Page";
        break;

    case "contact":
        echo "Welcome to the Contact Page";
        break;

    default:
        echo "Page not found";
}
?>

Output:

Welcome to the About Page

In PHP, traditional switch comparisons use loose comparison rules. Case matching is not automatically case-insensitive for strings, so "about" and "About" should not be assumed to match.

9. Switch vs. If-Else
Switch If-Else
Useful for comparing one expression against several case values. Useful for simple or complex Boolean conditions.
Uses case labels. Uses conditions.
Uses break to prevent fall-through. Does not require break between branches.
Can include a default case. Can include an else block.

Example using if-else:

<?php
$age = 20;

if ($age >= 18) {
    echo "Adult";
} else {
    echo "Minor";
}
?>

Output:

Adult

Use if-else when you need to test ranges or complex conditions. Use switch when selecting between several possible values.

📝 Practical Assignment

Write PHP programs to complete these exercises:

  1. Display the day name for a number from 1 to 7.
  2. Display a month name for a month number from 1 to 12.
  3. Create a calculator using +, -, * and /.
  4. Display a message for grades A, B, C, D and F.
  5. Group Saturday and Sunday into one Weekend case.
  6. Create a menu with home, about and contact options.
  7. Display "Invalid choice" when no case matches.
  8. Write an example showing what happens when break is omitted.

Sample starting code:

<?php
$month = 4;

switch ($month) {
    case 1:
        echo "January";
        break;

    case 2:
        echo "February";
        break;

    case 3:
        echo "March";
        break;

    case 4:
        echo "April";
        break;

    default:
        echo "Invalid month";
}
?>

Expected output:

April

🧠 Quick Quiz

1. Which keyword is used to define a case in a switch statement?



2. What is the purpose of break in a switch statement?



3. Which block runs when no case matches?



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