Base

The term base has two common meanings:

• Base class: a parent class from which other classes inherit. A base class defines common attributes and behavior shared by all subclasses. A base class is declared with class and extended with extends. Abstract base classes use the abstract keyword to enforce method implementation in subclasses

• Numeric base: the number of unique digits in a positional numeral system. PHP natively supports base 2, binary, base 8, octal, base 10, decimal, and base 16, hexadecimal integer literals. The base_convert(), bindec(), octdec(), decoct(), hexdec(), and dechex() functions convert between bases

• Base 64 encoding: an encoding method a binary-to-text encoding scheme that represents binary data in an ASCII string format.

<?php

// Base class (parent class)
abstract class Shape {
    abstract public function area(): float;
}

class Circle extends Shape {
    public function __construct(private float $radius) {}
    public function area(): float { return M_PI * $this->radius ** 2; }
}

// Numeric base conversions
echo base_convert('ff', 16, 10); // 255  (hex -> decimal)
echo base_convert('255', 10, 2); // 11111111  (decimal -> binary)

echo 0b11111111; // 255  (binary literal)
echo 0xFF;       // 255  (hex literal)
echo 0377;       // 255  (octal literal)

?>

Documentation

See also base_convert - PHP Manual.

Related : Abstract Class, Inheritance, Numeric Base, Base Class, Binary, Hexadecimal Integer, Base 64 Encoding