CODEWITHSUNDEEP
c#double
6godddd
6godddd

Reputation: 35

What is the letter after a double declaration in Csharp?

For example: 

private const double MAX_BATTERIJ = 100D, MIN_BATTERIJ = 0D;

What is the D here? I've also seen an m but have no clue what it does.

Upvotes: 1

Views: 1615

Answers (3)

Peter Stjernholm Meldgaard
Peter Stjernholm Meldgaard

Reputation: 250

It is the language reserved type indicator, indicating what type the literal number should be interpreted to. A way to understand this is looking at some code:

var x = 20D;
Console.WriteLine(x.GetType()); // Will write System.Double
var y = 20M;
Console.WriteLine(y.GetType()); // Will write System.Decimal

Here it is obvious that the compiler casts the literal type of the number 20 using the type indicator to the matching var type. Without the suffix it would not know which type of variable to create the "var" as. It could be an int, a decimal, a double and so on. Without you might later use is against another type and experience a type/cast exception trying to use as the wrong type.

Hope this way of seeing it helps clarify the use.

There is also a great tutorial on the subject here https://www.c-sharpcorner.com/article/data-type-suffixes-in-c-sharp/

Upvotes: 1

fubo
fubo

Reputation: 45987

Real literals The type of a real literal is determined by its suffix - reference

decimal x = 20M;  //decimal
double x = 20D;   //double
float x = 3.3F;   //float

site note - there are also Integer literals reference 

long x = 20L;     //long   
uint x = 2U;      //Unsigned Int
ulong x = 2UL;    //Unsigned Long
double x = 2.1E2; //exponent (210)
int x = 0xCA;     //hex

Upvotes: 6

Sean
Sean

Reputation: 62522

It indicates that the value is a double.

You can use f or F for float, d or D for double and m or M for decimal.

See here for more information on floating point suffixes.

Upvotes: 1

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