vimwiki

C# basics

Basic input/output

Console.WriteLine("Enter your name: "); 
 
name = Console.ReadLine();

Comment

// This is a single line comment

/* This is a multi-line comment
   and continues until the end */

Logical operato

Comparison operator

==
!=
>
>=
<
<=

Control flow

if statements

if (true)
{

}

else if (false)
{

}

else
{

}

Switch

switch (variable)
{
   case "1":
      // code
      break;

    case "2":
      // code
      break;

   default:
      // code
      break;
}

For loop

for (initialisation; stopping condition; iteration statement) ```C# for (int i = 0; i < 10; i++) {

}

## For each loop
- run x time the number of element in a given collection
- initiate a variable with each loop

```C#

string[] states = { "Alabama", "Alaska", "Arizona", "Arkansas", "California", "Colorado" };

foreach (string state in states) {
  Console.WriteLine(state);
}

While loop

int x = 0;
while (x < 3)
{
   x ++;
}

Do while loop

like a while loop but garantee one iteration even if condition false
```
int x = 0;
do 
{
 x ++;
} while (x < 3);
```

Jump statement

break
continue
return

while (true) {
  Console.WriteLine("This prints once.");
  // A `break` statement immediately terminates the loop that contains it.
  break;
}

for (int i = 1; i <= 10; i++) {
  // This prints every number from 1 to 10 except for 7.
  if (i == 7) {
    // A `continue` statement skips the rest of the loop and starts another iteration from the start.
    continue;
  }
  Console.WriteLine(i);
}

static int WeirdReturnOne() {
  while (true) {
    // Since `return` exits the method, the loop is also terminated. Control returns to the method's caller.
    return 1;
  }
}

Ternary Operator

condidtion ? expression true : expression false; if condition true, return expression 1 else expression 2

string ternary = isRaining ? "Umbrella" : "No Umbrella";

Variable and types

Data Type	Description	Memory Size
`bool`	Boolean	1 byte
`byte`	Byte	1 byte
`sbyte`	Short Byte	1 byte
`char`	Character	2 bytes
`decimal`	Decimal	16 bytes
`double`	Double	8 bytes
`float`	Float	4 bytes
`int`	Integer	4 bytes
`uint`	Unsigned Integer	4 bytes
`nint`	Native Integer	4 or 8 bytes
`unint`	Unsigned Native Integer	4 or 8 bytes
`long`	Long	8 bytes
`ulong`	Unsigned Long	8 bytes
`short`	Short	2 bytes
`ushort`	Unsigned Short	2 bytes

Declaration

bool isOpen = true;
byte age = 45;
sbyte temperature = 58;
char grade = 'a';
decimal numberOfAtoms = 1493867940.23m;
double weightOfHippos = 243906.12;
float heightOfGiraffe = 908.32f;
int seaLevel = -24;
uint year = 2023u;
nint pagesInBook = 412;
unint milesToNewYork = 2597;
long circumferenceOfEarth = 25000l;
ulong depthOfOcean = 28000ul;
short tableHeight = 4;
ushort treeBranches = 33;

Array

// if initialisation 
int[] arrayName = new int[] {1, 2, 3};
// or
int [] arrayName = {1, 2, 3}

// no initialisation
int[] arrayName = new int[5]

myIntArray[0] = 1; 

List

In C#, a list is a dynamic array that can grow or shrink in size.

// declaration
List<int> myIntList = new List<int>();
// or 
List<int> myIntList = new List<int>() {1, 2, 3};

myIntList.Add(1);

int firstElement = myIntList[0];

int count = myIntList.Count; // Get the count of elements in the list

myIntList.Remove(2); 

bool containsElement = myIntList.Contains(3);

Enum

In C#, an enum (short for “enumeration”) is a set of named constants that represent distinct values of a particular type. Enums are used to define a set of values that are meaningful and represent a discrete set of options or states.

enum DaysOfWeek
{
    Sunday,
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday
}

DaysOfWeek today = DaysOfWeek.Monday; // Declare and initialize a variable with an enum value

if (today == DaysOfWeek.Monday)
{
    Console.WriteLine("Today is Monday"); // Check the value of the enum variable
}