As a Junior developer, i've always been scared of learning 'Old' programming language that primarily uses OOP paradigm. However, today I decided to suck it up and at least try it. It isn't as bad as I think, there's similarities that it carries over to Javascript. Let us go through the basics first.

This blog assumes understanding of javascript

The Basic

Data Types

Unlike javascript which is dynamically typed language, C# is statically typed language: The data type of a variable is known at the compile time which means the programmer has to specify the data type of a variable at the time of its declaration.

int: number (32bit)
decimal: number (128bit)
string: string
bool: Boolean
list[]: Array
dictionary{}: Object

-------------- Declaration ----------------
int myInt = 2147483647;
decimal myDecimal = 0.751m; // The m indicates it is a decimal
string myString = "Hello World"; // Notice the double-quotes
bool myBool = true;

List/Array

Note: You cannot add or extend the length if you use method 1 & 2
Declaring & assigning List method 1

string[] myGroceryArray = new string[2]; // 2 is the length
myGroceryArray[0] = "Guacamole";

Declaring & assigning List method 2

string[] mySecondGroceryArray = { "Apples", "Eggs" };

Declaring & assigning List method 3

List myGroceryList = new List() { "Milk", "Cheese" };
Console.WriteLine(myGroceryList[0]); //"Milk"
myGroceryList.Add("Oranges"); //Push new item to array

Declaring & assigning Multi-dimensional List

The number of ',' will determine the dimensions

string[,] myTwoDimensionalArray = new string[,] {
    { "Apples", "Eggs" },
    { "Milk", "Cheese" }
};

IEnumerable/Array

An array that is specifically used to enumerate or loop through.

You may ask, "What's the difference with list?". The answer is:

One important difference between IEnumerable and List (besides one being an interface and the other being a concrete class) is that IEnumerable is read-only and List is not.

List myGroceryList = new List() { "Milk", "Cheese" };

IEnumerable myGroceryIEnumerable =  myGroceryList;

Dictionary/Object

Dictionary myGroceryDictionary = new Dictionary(){
    {"Dairy", new string[]{"Cheese", "Milk", "Eggs"}}
};

Console.WriteLine(myGroceryDictionary["Dairy"][2]);

Operators

Operators in C# behaves very similar to javascript so I won't describe it here

Conditionals

//Logic gate
  //There's no === in C#
myInt == mySecondInt 
myInt != mySecondInt 

myInt >= mySecondInt
myInt > mySecondInt
myInt 




  
  
  Loops



? Using foreach will be much faster than regular for loop




int[] intArr = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

int totalValue = 0;

for (int i = 0; i 




  
  
  Method


C# is first and foremost an OOP oriented language.



namespace HelloWorld
{
    internal class Program
    {
        static void Main()
        {
            int[] numArr = [1, 2, 3, 4, 5];
            int totalSum = GetSum(numArr);
        }

        static private int GetSum(int[] numArr)
        {
            int totalValue = 0;
            foreach (var item in numArr)
            {
                totalValue  = item;
            }
            return totalValue;
        }
    }
}





  
  
  Declaring Namespace & Model


Namespace is used to organization purpose, typically to organize classes



namespace HelloWorld.Models
{
    public class Computer
    {
        public string Motherboard { get; set; } = "";
        public int CPUCores { get; set; }
        public bool HasWIfi { get; set; }
        public bool HasLTE { get; set; }
        public DateTime ReleaseDate { get; set; }
        public decimal Price { get; set; }
        public string VideoCard { get; set; } = "";
    };
}





Starting C# 10, we can also declare namespace as such




namespace SampleNamespace;

class AnotherSampleClass
{
    public void AnotherSampleMethod()
    {
        System.Console.WriteLine(
            "SampleMethod inside SampleNamespace");
    }
}





  
  
  Importing Namespace




using HelloWorld.Models;