Branching Statements

Branching statements (conditionals) enable a PHP script to select from among different branches (or blocks of code) in the program's execution.

The if statement
if (conditional expression) { // If this expression evaluates to TRUE block of code;             // This block of code is executed; otherwise it's skipped } if (conditional expression) { // If this expression evaluates to TRUE block of code;             // This block of code is executed. } else { another block of code;     // This block is executed if the expression is FALSE } $n = 55; if ($n % 5 == 0) { echo "$n is divisible by 5"; } else { echo "$n is NOT divisible by 5"; }
 * The (optional) else clause is executed when the conditional expression is FALSE.
 * Examples

if ($n % 10 == 5 && $n * 2 < 100) { echo "$n is divisible by 5 and its value doubled is less than 100 "; } else { echo "Either $n is NOT divisible by 5 or its value doubled is not less than 100"; }

The elseif statement
The elseif statement lets you combine a number of unique alternatives into a single statement. if ($username == "Admin"){ echo "Welcome to the admin page"; } elseif ($username == "Guest") { echo "Welcome. Have a look around"; } else { echo "Welcome back, $username"; }

The ternary ? operator
The ? operator is like an if statement except it returns a value from one of the two expressions depending on the value of its conditional: (conditional expression) ? return_if_true : return if false ;

$logged_in = TRUE; $user = "Admin"; $banner = ($logged_in==TRUE) ? "Welcome back, $user!" : "Please login"; echo $banner;

The switch statement
The switch statement provides a multiway selection structure. Depending on the value of a variable, one of several branches is selected. It requires the use of the break statement. switch ($username) { case "Admin": echo "Welcome to the Admin page"; break; case "Guest": echo "Welcome. Have a look around"; break; default: echo "Welcome back, $username"; }

Homework: Problem 4-11
Write a switch statement that adds, subtracts, multiplies, or divides x using the action variable. Click here for a solution.

Branching statements (conditionals) enable a PHP script to select from among different branches (or blocks of code) in the program's execution.

The if statement
if (conditional expression) { // If this expression evaluates to TRUE block of code;             // This block of code is executed; otherwise it's skipped } if (conditional expression) { // If this expression evaluates to TRUE block of code;             // This block of code is executed. } else { another block of code;     // This block is executed if the expression is FALSE } $n = 55; if ($n % 5 == 0) { echo "$n is divisible by 5"; } else { echo "$n is NOT divisible by 5"; }
 * The (optional) else clause is executed when the conditional expression is FALSE.
 * Examples

if ($n % 10 == 5 && $n * 2 < 100) { echo "$n is divisible by 5 and its value doubled is less than 100 "; } else { echo "Either $n is NOT divisible by 5 or its value doubled is not less than 100"; }

The elseif statement
The elseif statement lets you combine a number of unique alternatives into a single statement. if ($username == "Admin"){ echo "Welcome to the admin page"; } elseif ($username == "Guest") { echo "Welcome. Have a look around"; } else { echo "Welcome back, $username"; }

The ternary ? operator
The ? operator is like an if statement except it returns a value from one of the two expressions depending on the value of its conditional: (conditional expression) ? return_if_true : return if false ;

$logged_in = TRUE; $user = "Admin"; $banner = ($logged_in==TRUE) ? "Welcome back, $user!" : "Please login"; echo $banner;

The switch statement
The switch statement provides a multiway selection structure. Depending on the value of a variable, one of several branches is selected. It requires the use of the break statement. switch ($username) { case "Admin": echo "Welcome to the Admin page"; break; case "Guest": echo "Welcome. Have a look around"; break; default: echo "Welcome back, $username"; }

Homework: Problem 4-11
Write a switch statement that adds, subtracts, multiplies, or divides x using the action variable. Click here for a solution.