If-Else Statement in PHP

In this tutorial, we will learn about if-else statements in PHP. We will cover the basics of conditional execution using if-else statements.

What is an If-Else statement

An if-else statement is a conditional statement that executes one block of code if a specified condition is true, and another block of code if the condition is false.

Syntax

The syntax for the if-else statement in PHP is:

if (condition) {
    // Code block to execute if condition is true
} else {
    // Code block to execute if condition is false
}

The if-else statement evaluates the specified condition. If the condition is true, the code block inside the if statement is executed; otherwise, the code block inside the else statement is executed.

Flowchart of If Else Statement

Example 1: Checking if a Number is Even or Odd

  1. Declare a variable $num.
  2. Assign a value to $num.
  3. Use an if-else statement to check if $num is even or odd.
  4. Print a message indicating whether $num is even or odd.

PHP Program

<?php
$num = 10;
if ($num % 2 == 0) {
    echo "$num is even.";
} else {
    echo "$num is odd.";
}
?>

Output

10 is even.

Example 2: Checking if a String Starts with a Specific Value

  1. Declare a variable $str.
  2. Assign a value to $str.
  3. Use an if-else statement to check if $str starts with a specific value.
  4. Print a message indicating the result of the check.

PHP Program

<?php
$str = "Hello, world!";
if (strpos($str, 'Hello') === 0) {
    echo "String starts with 'Hello'.";
} else {
    echo "String does not start with 'Hello'.";
}
?>

Output

String starts with 'Hello'.

Example 3: Checking if a Number is Positive or Negative

  1. Declare a variable $num.
  2. Assign a value to $num.
  3. Use an if-else statement to check if $num is positive or negative.
  4. Print a message indicating whether $num is positive or negative.

PHP Program

<?php
$num = -5;
if ($num > 0) {
    echo "$num is positive.";
} else {
    echo "$num is negative or zero.";
}
?>

Output

-5 is negative or zero.