Programming 1. Variables

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()

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Basic arithmetic operations

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

Extra: Modulo operator

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

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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: