C# Basic Concepts

Introduction

C# is a statically-typed programming language, meaning everything will have a type at compile-time. When we assing a value to a name, it is called as defining a variable. We can define a variable either by explicitly specifying it’s type or by letting the complier infer it’s type based on the assigned value(type inference).

int expVar = 7; // Explicitly typed
var impVar = 7; // Implicitly typed

Object Oriented Concepts

• C# is an object-oriented language and requires all the functions to be defined in a class.
• The class keyword is used to define a class.
• Objects (or instances) are created by using the new keyword.

  class Calculator
  {
    // ...
  }
  var calculator = new Calculator();
  

• A function within a class is referred to as a method.
• Each method can have zero or more parameters.
• All parameters must be explicitly typed, there is no type inference for parameters
• The return type must also be made explicit.
• Values are returned from methods using the return keyword. To allow a method to be called by code in other files, the public access modifier must be added.

  class Calculator
  {
    public int Add(int x, int y)
    {
        return x + y;
    }
  }
  

• Methods are invoked using dot (.) syntax on an instance

var calculator = new Calculator();
var sum_v1 = calculator.Add(1, 2);
var sum_v2 = calculator.Add(x: 1, y: 2);

• Scope in C# is defined between the { and } characters.
• C# supports single line comments // and multi-line comments inserted betewwn /* and */