Variables! — The building blocks of programming

You can think of variables as boxes to store some information to be referenced and manipulated in a program. We can use variables for the speed of a player, the current score of the game, the remaining lives, the skin color and basically for any element that needs a value in our games.

Creating a variable in C#

First of all, you have to create a script in Unity and attach it to a GameObject in your scene:

In order to create a variable in a C# script in your Unity project you have to follow this syntax:

Ok, lets explain each element of this line one by one:

• Access modifier: indicates where the variable can be used, public means that you can access from any script and private the variable can be used by code in the same class.
• Type: following the analogy from the beginning of the article, before storing something in the box we have to define what type of thing you can put in it. In C# the basic types are int (whole number), float (number with decimals), string (set of characters) and bool (true or false).
• Name: a label to identify your variable.
• Value (optional): The information to store in your variable.

Basic operations:

Usually when we use variables we have to modify their values at some moment, for example, if the player is hitted by an enemy he loses a life, or if he picks up a power up increases the attack power.

To change the value you can use the assignment operator (=), and we can use the arithmetic operators (+, -, *, /) for different calculations:

Example

The next code show you a simple “Player” script with some variables declared commonly used in many games: