1. Variables

About C#

  • C# is a general-purpose object-oriented language
  • Created by Microsoft in 2000 as a competitor for Java
  • Syntax
    • Pretty much everything will be inside a class
    • Curly brackets { and } mark the bodies of statements
      • Namespaces, classes, functions...
  • Semicolon at the end of most statements
    • VS code tells if it's missing!

C# syntax example

using System;

namespace MyAwesomeProgram
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}
  • In Unity, we don't (necessarily) have to deal with namespaces.

Variable declaration

int number = 1;
  1. Modifiers (not necessary)
  2. Type declaration
  3. Variable name
  4. Initial value (not necessary) after =
  5. Line ending with ;

Commenting

  • one line
    // one line comment
  • multiline
    /* this is a
multi-line
comment */
  • Comments are not executed
  • Use to
    1. explain your intent
    2. comment out actual code for testing and debugging

The most important variable types

  • bool: truth value (true / false)
bool booleanValue = true;
  • int: whole number
int wholeNumberValue = 3;
  • double & float: decimal number (double = double precision)
float numberValue = 3.0f;
  • string: text field
string text = "text is here";

Modifiers

  • A common modifier to add in front of a variable is const, short for constant
  • If we know that a value of a variable is never going to change during the execution of the script, we can set it to const:
    const string text = "I never change!";
  • Other modifiers include access modifiers.

Unity Console

  • Console Window
    • Error messages
    • Debug messages
  • Debug.Log(textVariable)
    • Use it to print stuff into the console
    • As the name suggests, it's used for debugging
    • You can print other variable types as well, not only strings!
  • Debug.LogWarning()
  • Debug.LogError()

Basic arithmetic operations

  • + (addition)
  • - (subtraction)
  • * (multiplication)
  • / (division)

Extra: Modulo operator

  • %
    • modulo operator (remainder)
    • great for looping a range

Exercise 1: Trying out variables

  • Create a new Unity project for simple programming exercises.

  • Create a new C# script component inside an empty GameObject.

  • Declare two variables a and b with the type double.

  • In the Start() function, print to console four operations: the sum, difference, fraction and product.

  • What happens if either of them is equal to zero?

Reading

Microsoft's own C# Reference is a great way to dive deeper into the language.

Some basics covering the syntax in C# are covered here: