PHP and Algorithmic Thinking for the Complete Beginner

Chapter 11 Manipulating Numbers

11.1 Introduction

Just like every high-level programming/scripting language, PHP provides many ready-to-use subprograms (functions) that you can use whenever and wherever you wish.

A “subprogram” is simply a group of statements packaged as a single unit. Each subprogram has a descriptive name and performs a specific task.

In PHP subprograms are called “functions”.

To better understand PHP's functions, let's take Heron's^[11] iterative formula that calculates the square root of a positive number.

.

where

►y is the ...