PHP, scalar types

In PHP, scalar types represent single, indivisible values (as opposed to compound types like arrays or objects). PHP supports four scalar types:

---

1. bool (Boolean)

• Represents a truth value: true or false.
• Often used in conditional statements.
• Example:

  $is_active = true;
  $is_logged_in = false;
  

---

2. int (Integer)

• Represents whole numbers (positive, negative, or zero).
• Size depends on the system (typically 32-bit or 64-bit).
• Example:

  $age = 25;
  $temperature = -10;
  

---

3. float (Floating-Point Number)

• Represents numbers with a decimal point or in exponential form.
• Also called double (synonymous in PHP).
• Precision is platform-dependent.
• Example:

  $price = 19.99;
  $scientific = 1.2e3; // 1200
  

---

4. string

• Represents a sequence of characters (text).
• Can be declared with single quotes ('), double quotes ("), or heredoc/nowdoc syntax.
• Example:

  $name = 'Alice';
  $greeting = "Hello, $name!"; // Double quotes parse variables
  

---

Key Notes:

• Type Declaration (Type Hinting):
  Since PHP 7, you can enforce scalar types in function parameters and return values:

  function add(int $a, int $b): int {
      return $a + $b;
  }
  echo add(5, 3); // 8 (strict mode enforces types)
  

• Strict vs. Coercive Typing:
  By default, PHP coerces types (e.g., converting "5" to 5). Enable strict typing to enforce exact types:

  declare(strict_types=1); // Must be the first line in the script
  

• Type Checking:
  Use gettype() or is_* functions:

  $value = 42;
  echo gettype($value); // "integer"
  is_int($value);       // true
  is_string($value);    // false
  

---

Scalar vs. Compound Types:

Scalar Types	Compound Types
Single values	Collections of values
bool, int, float, string	array, object, callable, iterable

---

Example: All Scalar Types

declare(strict_types=1);

function displayTypes(
    bool $flag,
    int $number,
    float $decimal,
    string $text
): void {
    echo "Boolean: " . ($flag ? 'true' : 'false') . "\n";
    echo "Integer: $number\n";
    echo "Float: $decimal\n";
    echo "String: $text\n";
}

displayTypes(true, 100, 3.14, "PHP Scalars");

Output:

Boolean: true
Integer: 100
Float: 3.14
String: PHP Scalars

Scalar types are fundamental for data handling, calculations, and logical operations in PHP. Use type declarations for robust, error-resistant code! 🚀

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