Conditional Statements

Conditional statements are used to perform different actions based on different conditions. Very often when writing code, you want to perform different actions for different conditions, which is made possible by statements such as if, else, and switch. They give your program the ability to "make decisions" on which path to take.

EXAMPLE

[file:The if statement]
<?php
 echo " Conditional if statement: ";

$number = 10;

// Check if the number is greater than 5
  if ($number > 5) {
    echo "The number is greater than 5.";
  }

echo " ";
?>

[file:if...elseif...else]
<?php
 echo " Conditional structure: ";

$number = 3;

// Check different conditions consecutively
 if ($number > 5) {
 echo "The number is greater than 5.";
 } elseif ($number < 5) {
 echo "The number is less than 5.";
 } else {
 echo "The number is equal to 5.";
 }

echo " ";
?>

[file:Nested if statements]
<?php
 echo " Checking multiple conditions at once: ";

$balance = true;
  $number = 10;

// Checking a condition inside another condition
  if ($balance) {
    if ($number > 0) {
      echo "The number is positive and the system is balanced.";
    } else {
      echo "The system is balanced, but the number is not positive.";
    }
  } else {
    echo "The system is not balanced.";
  }

echo " ";
?>

[file:The switch statement]
<?php
 echo " Checking values with switch: ";

$input = "10"; // Simulating user input (you can change this to "-5" or "0")

if (is_numeric($input)) {
    $number = (float)$input;

switch (true) {
 case ($number > 0):
 echo "The number $number is positive.";
 break;
 case ($number < 0):
 echo "The number $number is negative.";
 break;
 case ($number == 0):
 echo "The number is equal to zero.";
 break;
 default:
 echo "Unknown value error.";
 break;
 } 
 } else {
 echo "The input '$input' is not a valid number.";
 }

echo " ";
?>

RESULT

The result will be displayed here...

Overview of Conditional Statements in PHP

In PHP, we have three main ways to check conditions and direct the flow of the program:

if: The most basic statement. It executes a block of code inside curly braces only if the specified condition evaluates to true (true).
if...elseif...else: Allows checking multiple consecutive conditions. The code block that corresponds to the first true condition will execute. If none of the conditions are met, the default code inside the else block will run.
switch: An elegant and cleaner alternative to the if-elseif structure when you want to check a single variable against multiple distinct fixed values (known as cases or case statements).

🛠️ Essential Tools for Conditions: Comparison and Logical Operators

To write a condition inside the parentheses of an if statement, we use operators. Here are the ones you need to know:

Value Comparison: == (equal), === (identical - equal value and type), != (not equal), < (less than), > (greater than).
Combining Conditions (Logical): && (AND – both conditions must be true) and || (OR – at least one of the conditions must be true).