? PHP If Statement

? Quick Overview

The if statement in PHP is used to execute code only when a specified condition evaluates to true. It plays a critical role in decision-making and controlling the flow of a PHP program.

? Key Concepts

Conditions are evaluated as true or false
Comparison operators are commonly used inside conditions
Multiple conditions can be chained using elseif and else
Nested if statements allow complex decision logic

? Syntax / Theory

The PHP if statement checks a condition and executes the block of code only if that condition is satisfied. If the condition is false, the code inside the block is skipped.

? Logic Playground (Interactive)

Test the logic: Enter a numeric Score (0-100) to see the if...elseif logic in action.

Result will appear here...

This simulates how PHP would evaluate your input based on score thresholds.

? Basic If Statement

? View Code Example

// Check if the user is eligible to vote
<?php
$age = 20;

if ($age >= 18) {
echo "You are eligible to vote.";
}
?>

? If...Else Statement

? View Code Example

// Decide pass or fail based on marks
<?php
$marks = 40;

if ($marks >= 50) {
echo "You passed the exam.";
} else {
echo "You failed the exam.";
}
?>

? If...Elseif...Else Statement

? View Code Example

// Display greeting based on time
<?php
$time = 15;

if ($time < 12) {
echo "Good Morning!";
} elseif ($time < 18) {
echo "Good Afternoon!";
} else {
echo "Good Evening!";
}
?>

? Nested If Statement

? View Code Example

// Check both age and citizenship for voting
<?php
$age = 25;
$citizen = true;

if ($age >= 18) {
if ($citizen) {
echo "You can vote in elections.";
} else {
echo "You must be a citizen to vote.";
}
}
?>

? Live Output / Explanation

Based on the input values, PHP evaluates each condition and executes only the matching block. This ensures the program responds differently depending on user data or system state.

? Interactive Concept

Imagine a decision tree where each condition branches the execution path. Nested if statements allow PHP to evaluate multiple layers of logic step by step.

? Use Cases

User authentication and authorization checks
Form validation logic
Displaying content based on time, role, or status
Business rules and eligibility checks

✅ Tips & Best Practices

Use clear and readable conditions
Avoid deeply nested if blocks when possible
Use elseif instead of multiple independent if statements

? Try It Yourself

Create a script to check if a number is positive, negative, or zero
Check student discount eligibility based on age
Use nested conditions to validate login and role access