Working with Numbers | Free PHP & MySQL Tutorial

This tutorial provides a comprehensive understanding of arithmetic and assignment operators in PHP & MySQL, including how to increment variables and use assignment operators in your code. It's a perfect resource for those starting with PHP programming, aiming at careers in back end development.

Key Insights

Arithmetic operators in PHP include addition, subtraction, multiplication, division and modulus.
Assignment operators in PHP allow the incrementing of a variable value directly, such as $myVar += 5 which is equivalent to $myVar = $myVar + 5.
The tutorial provides code examples for using arithmetic and assignment operators within PHP scripts, including the increment operator.
The exercise guides you to use these operators in a PHP script, observe the output, and understand how these operators function.
The table of arithmetic operators and assignment operators provide a quick reference for operators used in PHP.
The understanding of these operators is fundamental to PHP programming and essential for careers in back end development.

This exercise is excerpted from Noble Desktop’s past app development training materials and is compatible with iOS updates through 2021. To learn current skills in web development, check out our coding bootcamps in NYC and live online.

Note: These materials are provided to give prospective students a sense of how we structure our class exercises and supplementary materials. During the course, you will get access to the accompanying class files, live instructor demonstrations, and hands-on instruction.

Topics covered in this PHP & MySQL tutorial:

Arithmetic operators, Assignment operators, Table of arithmetic operators, Table of assignment operators

Exercise Overview

Math! Who doesn’t love it? OK, maybe not everyone loves math, but as programmers it’s something we end up doing quite a bit of. Here we’ll explore how PHP works with numbers.

Arithmetic Operators

In your code editor, open math.php from the phpclass folder.
In between the <body> tags add the following bold code:
```
<?php 
   $myVar = 2;
   $myVar = $myVar + 1;
   echo $myVar;
?>
```
This code makes a new variable called $myVar with the value of 2, adds 1 to it, and then displays the new value.
Save the page and then in a browser go to:
- Mac: localhost:8888/phpclass/math.php
- Windows: localhost/phpclass/math.php
The page should read:

3
Switch back to your code editor.
We can also increment the variable by 1. Select the last two lines, then replace them with the following bold code:
```
<?php 
   $myVar = 2;
   $newVar = $myVar++;
   echo '$myVar: ' . $myVar;
?>
```
This increments the value of $myVar by one.
Save the page, go to the browser, and reload math.php.

It should now say:

$myVar: 3

Assignment Operators

What if you wanted to increment the value of a variable directly and by a value other than one? You’d use what is called an Assignment Operator.

Switch back to your code editor.
Replace the last two lines with the following bold code:
```
$myVar = 2;
$myVar += 5;
echo $myVar;
```
This makes a variable called $myVar with the value of 2, adds 5 to it, and then displays the new value.

$myVar += 5 is equivalent to $myVar = $myVar + 5
Save the page, go to the browser, and reload math.php.

The screen should now say 7.
Close the file. We’re done with it.

Table of Arithmetic Operators

Operator	Meaning	Example
+	Addition	`$n + 1`
-	Subtraction	`$n - 5`
*	Multiplication	`$n * 20`
/	Division	`$n / 3`
%	Modulus (remainder)	`$n % 6`
++	Increment	`++$n`
`--`	Decrement	`--$n`

Table of Assignment Operators

Example	Meaning	Alternative Longhand Syntax
`$n = 3`	`$n equals 3`	`$n = 3`
`$n += 3`	`$n equals $n plus 3`	`$n = $n + 3`
`$n -= 3`	`$n equals $n minus 3`	`$n = $n - 3`
`$n *= 3`	`$n equals $n times 3`	`$n = $n * 3`
`$n /= 3`	`$n equals $n divided by 3`	`$n = $n / 3`
`$n %= 3`	`$n equals the remainder of $n divided by 3`	`$n = $n % 3`
`$n .= 3`	`$n equals $n concatenated with 3`	`$n = $n . 3`