🔢 PHP Integers – Declare, Use & Handle Numbers in PHP

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🧲 Introduction – Why Integers Are Essential in PHP

In PHP, integers are one of the most fundamental data types used for numeric operations. Whether you’re performing calculations, managing loop counters, handling pagination, or comparing values—integers are everywhere.

🎯 In this guide, you’ll learn:

• What integers are in PHP
• How to declare and use integers
• Common integer operations and best practices
• Built-in functions and type checking techniques

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📘 What Is an Integer in PHP?

An integer in PHP is a whole number (positive or negative) without a decimal point.

✅ Example

<?php
$age = 25;
var_dump($age); // int(25)
?>

✅ var_dump() confirms both the type and value of the variable.

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📏 Integer Syntax Rules

• Must contain only digits
• Can be positive or negative
• No decimal point (use float for decimal numbers)
• Can be specified in:
  • Decimal (Base 10) → 123
  • Octal (Base 8) → 0123 (starts with 0)
  • Hexadecimal (Base 16) → 0x1A
  • Binary (Base 2) → 0b1010

<?php
$dec = 100;
$oct = 0123;     // 83 in decimal
$hex = 0x1A;     // 26 in decimal
$bin = 0b1010;   // 10 in decimal

var_dump($dec, $oct, $hex, $bin);
?>

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🔍 Integer Type Checking and Conversion

✅ Check if a variable is an integer:

<?php
$num = 20;
var_dump(is_int($num)); // true
?>

✅ Cast other types to integer:

<?php
$price = "99.99";
$intPrice = (int) $price;
echo $intPrice; // Outputs: 99
?>

✅ Only the whole number part is preserved during casting.

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➕ Integer Arithmetic Operators

PHP supports all standard arithmetic operations on integers:

Operator	Operation	Example	Output
+	Addition	10 + 5	15
-	Subtraction	10 - 3	7
*	Multiplication	5 * 4	20
/	Division	10 / 2	5
%	Modulus (remainder)	10 % 3	1

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🔢 Integer Overflow

PHP integers are platform-dependent:

Platform	Max Integer Value
32-bit	2,147,483,647
64-bit	9,223,372,036,854,775,807

<?php
$x = PHP_INT_MAX;
echo $x; // Platform-dependent max value
?>

✅ Use PHP_INT_MAX and PHP_INT_MIN to safely handle boundaries.

💡 PHP automatically converts large integers to float if the value exceeds the limit.

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🔁 Real-World Example – Counter in a Loop

<?php
for ($i = 1; $i <= 5; $i++) {
    echo "Step $i<br>";
}
?>

✅ Integers are commonly used for counters, indices, and pagination.

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🧰 Useful Integer-Related Constants

Constant	Description
PHP_INT_MAX	Maximum representable integer
PHP_INT_MIN	Minimum representable integer
PHP_INT_SIZE	Size of integer in bytes

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🛡️ Best Practices

Best Practice	Why It Matters
✅ Use is_int() to validate input	Prevents logic errors and type bugs
✅ Use (int) to convert safely	Ensures correct format when needed
❌ Avoid operations near overflow limit	PHP may convert to float unexpectedly
✅ Use strict typing in functions if needed	Prevents unexpected type coercion

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📌 Summary – Recap & Next Steps

PHP integers are essential for counting, calculations, control structures, and loops. Understanding how integers behave across platforms and how to manipulate them ensures better logic flow, performance, and code stability.

🔍 Key Takeaways:

• Integers are whole numbers (no decimals)
• PHP supports decimal, octal, hex, and binary formats
• Use is_int() and (int) for checking and casting
• Be aware of PHP_INT_MAX and potential overflow
• Used extensively in loops, conditions, pagination, math, etc.

⚙️ Real-World Relevance:
From managing inventory and scores to rendering dynamic table rows or loop-based operations — integers power practical business logic in nearly every PHP application.

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❓ Frequently Asked Questions (FAQ)

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❓ What is the default integer type in PHP?
✅ PHP uses signed integers and automatically determines bit length based on your system architecture (32-bit or 64-bit).

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❓ What happens when an integer exceeds the max limit?
✅ It’s converted to a float automatically.

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❓ How can I check if a variable is an integer?
✅ Use is_int() or is_integer() (both are the same).

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❓ Can I store numbers with decimals as integers?
❌ No. Use float for decimal numbers.
✅ You can cast them to int to keep the whole part only.

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❓ Are octal and hexadecimal used in real PHP apps?
✅ Rarely — but useful in bitwise operations, encryption, or system-level scripting.

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