Understanding variables

In the previous chapter, we saw how variables are written and touched on the high-level functionality that they provide. However, we're still missing the syntax that makes all of that possible.

Declaring variables

Variables don't just appear at the top of a C# script; they have to be declared according to certain rules and requirements. At its most basic level, a variable statement needs to satisfy the following requirements:

• The type of data the variable will store needs to be specified
• The variable has to have a unique name
• If there is an assigned value, it must match the specified type
• The variable declaration needs to end with a semicolon

The result of adhering to these rules is the following syntax:

dataType UniqueName = value;

Variables need unique names to avoid conflicts with words that have already been taken by C#, which are called keywords. You can find the full list of protected keywords at: https://docs.microsoft.com/en-us/dotnet/csharp...

Introducing operators

Operator symbols in programming languages represent the arithmetic, assignment, relational, and logical functionality that types can perform. Arithmetic operators represent basic math functions, while assignment operators perform math and assignment functions together on a given value. Relational and logical operators evaluate conditions between multiple values, such as greater than, less than, and equal to.

C# also offers bitwise and miscellaneous operators, but these won't come into play for you until you're well on your way to creating more complex applications.

At this point, it only makes sense to cover arithmetic and assignment operators; we'll get to relational and logical functionality when it becomes relevant in the next chapter.

Arithmetic and assignments

You're already familiar with the arithmetic operator symbols from school:

• + for addition
• - for subtraction
• / for division
• * for multiplication

C# operators follow the conventional...

Defining methods

In the previous chapter, we briefly touched on the role methods play in our programs; namely, that they store and execute instructions, just like variables store values. Now, we need to understand the syntax of method declarations and how they drive action and behaviour in our classes.

As with variables, method declarations have their basic requirements, which are as follows:

• The type of data that will be returned by the method (methods don’t all have to return anything, so this can be void)
• A unique name, starting with a capital letter
• A pair of parentheses following the method name
• A pair of curly brackets marking the method body (where instructions are stored)

Putting all of these rules together, we get a simple method blueprint:

returnType UniqueName() 
{ 
    method body 
}

Let's break down the default Start() method in LearningCurve as a practical example:

void Start() 
{
}

In the preceding output, we can see the following:

• The method starts with...

Summary

This chapter has been a fast descent from the basic theory of programming and its building blocks into the strata of real code and C# syntax. We've seen good and bad forms of code formatting, learned how to debug information in the Unity console, and created our first variables.

C# types, access modifiers, and variable scope weren't far behind, as we worked with member variables in the Inspector window and started venturing into the realm of methods and actions.

Methods helped us to understand written instructions in code, but more importantly, how to properly harness their power into useful behaviors. Input parameters, return types, and method signatures are all important topics, but the real gift they offer is the potential for new kinds of actions to be performed.

You're now armed with the two fundamental building blocks of programming; almost everything you'll do from now on will be an extension or application of these two concepts.

In the next chapter...

Pop quiz—variables and methods

1. What is the proper way to write a variable name in C#?
2. How do you make a variable appear in Unity's Inspector window?
3. What are the four access modifiers available in C#?
4. When are explicit conversions needed between types?
5. What are the minimum requirements for defining a method?
6. What is the purpose of the parentheses at the end of the method name?
7. What does a return type of void mean in a method definition?
8. How often is the Update() method called by Unity?