Learn the fundamentals of PHP from structural programming to object-oriented techniques.

Web Development with PHP

This highly interactive module introduces us to fundamental programming concepts in PHP—one of the most popular languages in the world. It begins with a simple “Hello, World!” program and proceeds to cover common concepts such as conditional statements, loop statements, and logic in PHP. It then reflects upon the idea of functions and arrays, as well as the power they give to the programmer to write better code.

Finally, it dives deeper into advanced concepts such as classes, inheritance, and exception handling in PHP. By the time we're done, we’ll have a good grip on the basics of PHP and will be ready to study advanced concepts.

Learn PHP from Scratch

# What is Pass by Reference?

When passing *arguments* by **pass by reference**, the *original* value is passed. Therefore, the *original* value gets altered. In **pass by reference**, we actually pass the value using *ampersand* sign `&`. The additional `&` is very important: it tells the *compiler* that the data is a *reference* to the *value* rather than simply the value itself.

# Example: Swap Numbers
Now let's redefine the `interchange` *function* from the example in the [previous](https://www.educative.io/courses/learn-php/pass-by-value) lesson. 

This lesson introduces the ways by which we pass values to a function by reference.
