C#

Front 1

CLR

Back 1

Common Language Runtime

Front 2

C#

Back 2

Programming Language

Front 3

. NET

Back 3

Framework for building applications on windows. .Net is not limited to C# and different languages such as VB or F#. It consists of CLR and a class library that we use for building applications.

Front 4

CLRs job is?

Back 4

Translate intermediate language code into machine code, called JIT or just in time compilation.

Front 5

C# is compiled into?

Back 5

Common Intermediate Language, it is byte code, a platform independent instruction set that can be executed in any environment.

Front 6

Namespace

Back 6

Container for related classes

Front 7

Assembly

Back 7

Container for related namespaces. It can be a dll or exe on disk. It's a single unit of deployment of. NET application. When you compile you are making an assembly.

Front 8

DLL

Back 8

Dynamically Linked Library

Front 9

What are System, System.Core, System.XML?

Back 9

Assemblies because they are dlls but they are also namespaces.

Front 10

JIT compilation

Back 10

The compilation of intermediate language code to native machine code by CLR, common language runtime, a virtual machine component of .NET.

Front 11

Constant

Back 11

An immutable value

Front 12

Variable

Back 12

A name given to a storage location in memory.

Front 13

Why use constants?

Back 13

For protection against changing, for safety.

Front 14

Byte, how many bytes and range?

Back 14

1 byte, 0 to 255

Front 15

short

Back 15

2 bytes, - 32,768 to 32,768

Front 16

int

Back 16

4 bytes, -2,1b to 2.1b

Front 17

long

Back 17

8 bytes

Front 18

decimal

Back 18

16 bytes, -7.9x10^28 to 7.9x10^28 real number, suffix is m

decimal dec = 4.5m;

Front 19

bool

Back 19

1 byte

Front 20

Double

Back 20

8 bytes, real number

Front 21

char

Back 21

2 bytes, unicode

Front 22

Overflowing

Back 22

exceeding the boundary of the datatype, to stop this use the checked keyword, this will throw an exception!

checked

{

byte number = 255;

number+=1;

}

Front 23

Scope

Back 23

Is where the variable is visible, so which part of the program can see the variable.

Front 24

var

Back 24

An implicit type and strongly typed variable where the compiler determines the type.

Front 25

Format String

Back 25

Console.WriteLine("{0} {1} {2}", var1, var2, var3);

A template of variables to substitute

Front 26

Implicit type conversion

Back 26

byte b = 1;

int i = b;

No problem converting because byte is smaller than int. So the compiler can convert implicitly.

Front 27

Explicit type conversion or casting

Back 27

int i = 1;

byte b = i;

Won't compile needs a cast or explicit conversion.

int i = 1;

byte b = (byte) i;

But this only works with convertible types.

Front 28

How to convert string to int?

Back 28

string s = "2";

int i = Convert.ToInt32(s);

int j = int.Parse(s);

Prefer Convert over int.Parse because int.Parse will throw an exception instead of returning null like Convert if the input is bad.

Front 29

Post fix, prefix incriment

int a =1;

int b = a++;

int c = ++b;

Back 29

a=2

b=2

c=2

Front 30

Will byte b = 500; compile?

Back 30

No because the compiler will check that it is between 0 and 255.

Front 31

Static modifier on main ?

Back 31

No need to create an object to call a static method. Static says there is only one instance. So 1 main function, which is why main is static and why you can call it from the class name.

Front 32

Struct vs class

Back 32

Structs can't have default constructor, so no parameterless constructor.

Structs are value type and are copied, classes are reference type.

Structs can be instantiated without using new.

Structs cannot inherit.

Structs are allocated on the stack.

Classes are created on the heap.

Front 33

Declaring arrays allows for different syntax.

Back 33

string[] names = {"Ralph", "Jake"} ;

string[] names = new string[] {"Ralph", "Jake"} ;

string[] names = new string[2] {"Ralph", "Jake"} ;

string[] names = new string[2];

Front 34

Are strings immutable?

Back 34

Yes, you need to create a new one to change it.

Front 35

How to create a verbatim string to not need escape backslash?

Back 35

Put an @ symbol in front of the string?

Front 36

String vs string

Int32 vs int

Back 36

String in System assembly or namespaces is the same as the keyword string.

Same for Int32 and int

Front 37

Can enums use something other than int?

Back 37

Yes

enum Temperature : byte

enum Temperature : short

enum Temperature : long

enum Temperature : ulong

Front 38

How to convert a string to enum?

Back 38

Enum.Parse(typeof(myenum), mystring);

Front 39

Arrays when copy, copy by reference or value?

Back 39

Copy by reference!

int[] myints = new int[1] {2};

int[] sameints = myints;

Front 40

What are Span<T> and Memory<T>

Back 40

A data structure that allows you access contiguous memory. You can test, change and convert elements in memory.

Span is on the stack, Memory is on the heap.

Span is not implemented in unity, but there is a way to get Memory. Can reuse memory with Memory by slicing.

We can edit inside of foreach loops when referencing value types which isn't available in List.

Front 41

Seed a random number generator?

Back 41

Random rand = new Random(Guid.NewGuid().GetHasCode());

Front 42

Difference between jagged array and rectangular array?

Back 42

int[,] array2d = new int[1,5];

Vs

int[,] array2d = new int[2,];

array2d[0] = new int[8];

array2d[1] = new int[2];

Front 43

When subtracting timespans in C# what does it give you?

Back 43

The difference in time between timespans.

Front 44

How to convert a string to a timespans?

Back 44

TimeSpan.Parse("01:02:03")

Will create a time span with 1 hour 2 minutes and 3 seconds.

Front 45

How do you get the current time?

Back 45

DateTime.Now

Front 46

Since DateTime is immutable what must you do to add time?

Back 46

DateTime dt = oldDT.AddYears(1)

Always return a new instance.

oldDT has not changed

Front 47

How to create a time span of 5 hours?

Back 47

TimeSpan.FromHours(5)

Front 48

How to get the current year?

Back 48

DateTime.Now.Year

Front 49

How to get rid of white space at the end or beginning?

Back 49

Trim

Front 50

To replace a given character or substring use?

Back 50

String.Replace("are", "aren't");

Front 51

How to tell string to format a number to currency with dollar sign?

Back 51

Convert a number to currency, or dollars.

Hint 51

int i = 1234;

i.ToString("C");

C is for currency.

Front 52

How to split strings on spaces?

Back 52

car names = Mystring.Split(" ");

Front 53

Best way to check if the string is good?

Back 53

String.IsNullOrEmpty(mystring);