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PHP - Integers

In PHP, an integer is a data type that represents a whole number without any fractional or decimal component. Integers can be positive, negative, or zero.

Defining Integers

You can define integers directly by assigning a whole number to a variable.

Example:

php
<?php
        $positiveInt = 123;
        $negativeInt = -456;
        $zero = 0;
        ?>

Integer Range

The range of integers depends on the platform (32-bit or 64-bit). On a 32-bit system, integers can typically range from -2,147,483,648 to 2,147,483,647. On a 64-bit system, the range is much larger, from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

Integer Literals

PHP supports different notations for integer literals:

1. Decimal (Base 10)

The most common form, using digits 0-9.

Example:

php
<?php
        $decimal = 42;
        ?>

2. Hexadecimal (Base 16)

Uses digits 0-9 and letters A-F, prefixed by 0x.

Example:

php
<?php
        $hexadecimal = 0x2A; // Equivalent to 42 in decimal
        ?>

3. Octal (Base 8)

Uses digits 0-7, prefixed by 0.

Example:

php
<?php
        $octal = 052; // Equivalent to 42 in decimal
        ?>

4. Binary (Base 2)

Uses digits 0-1, prefixed by 0b.

Example:

php
<?php
        $binary = 0b101010; // Equivalent to 42 in decimal
        ?>

Type Casting

You can explicitly cast a variable to an integer using (int) or (integer).

Example:

php
<?php
        $float = 3.14;
        $int = (int)$float; // $int is 3
        ?>

Integer Operations

PHP supports standard arithmetic operations with integers:

1. Addition (+)

Example:

php
<?php
        $a = 10;
        $b = 5;
        $sum = $a + $b; // $sum is 15
        ?>

2. Subtraction (-)

Example:

php
<?php
        $a = 10;
        $b = 5;
        $difference = $a - $b; // $difference is 5
        ?>

3. Multiplication (*)

Example:

php
<?php
        $a = 10;
        $b = 5;
        $product = $a * $b; // $product is 50
        ?>

4. Division (/)

Example:

php
<?php
        $a = 10;
        $b = 5;
        $quotient = $a / $b; // $quotient is 2
        ?>

5. Modulus (%)

Returns the remainder of the division.

Example:

php
<?php
        $a = 10;
        $b = 3;
        $remainder = $a % $b; // $remainder is 1
        ?>

Integer Functions

PHP provides several built-in functions to work with integers:

1. is_int() or is_integer()

Checks if a variable is an integer.

Example:

php
<?php
        $var = 123;
        if (is_int($var)) {
            echo "This is an integer.";
        } else {
            echo "This is not an integer.";
        }
        ?>

2. intval()

Returns the integer value of a variable.

Example:

php
<?php
        $var = "123abc";
        $intVal = intval($var); // $intVal is 123
        ?>

3. abs()

Returns the absolute value of an integer.

Example:

php
<?php
        $var = -123;
        $absVal = abs($var); // $absVal is 123
        ?>

Integer Overflow

When an integer exceeds the platform's maximum integer value, it will be interpreted as a float.

Example:

php
<?php
        $largeInt = PHP_INT_MAX + 1;
        var_dump($largeInt); // Output: float
        ?>

Summary:

Integers in PHP are used to represent whole numbers and support various notations such as decimal, hexadecimal, octal, and binary. PHP provides a wide range of operations and functions to work with integers. Understanding how to handle integers and their operations is fundamental for effective programming in PHP.