William Duffy

Glasgow Based C# ASP.NET Web Developer

C# Literal Types

Posted by William on Jan 13, 2010 • (4)

When you are specifying literal numeric values in your code you will, on occasion, have to give the compiler a heads-up on the expected type from the declaration.

For example, the literal value 5.3 will, by default, be assumed to be a double. As such, the following

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float result = 5.3 / 12.4;

will result in the exception

Cannot implicitly convert type ‘double’ to ‘float’. An explicit conversion exists (are you missing a cast?)

You could cast the value but that would create an unneccessary overhead and result in messy code.

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float result = (float)5.3 / (float)12.4; 
or
float result = (float)(5.3 / 12.4);

The most suitable way to approach this is to advise the compiler on the literal type. You do this by applying a suffix to your literal.

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float result = 5.3f / 12.4f;

This can also be used when passing a literal as a parameter in a method signature.

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MyObject.MyMethod(12.5m);

A table of the most common literal type declarations can be seen below.

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var x = 1m;  // decimal
var x = 1f;  // float
var x = 1d;  // double
var x = 1l;  // long
var x = 1u;  // uint
var x = 1ul; // ulong

Tagged as , , , + Categorized as ASP.NET, C#

4 Comments

  1. Dave the Ninja says:
    January 14th, 2010 at 1:45 am

    Welcome back Duffy! been a while since the last post!

    Ninja

    p.s I’m sure I told you all this at B.D Network :-)

  2. Steve Woods says:
    January 17th, 2010 at 1:11 pm

    I had no idea you could do this – i’ve been using the Cast method which, as you say, is messy – however I thought it was a limitation.

    Excellent post – now I have tons of code to refactor :(

  3. Gryphes says:
    October 22nd, 2010 at 12:36 pm

    you can also use
    @ as a literal type when using “\’ with string especially C# considers the \- backspace as a escape character if you don’t append @ at the beginning of that string it will generate an error.

    string Wincal = @”Microsoft\Windows\WindowsCalc”;

Trackbacks & Pingbacks

  1. Tweets that mention C# Literal Types | William Duffy -- Topsy.com
    January 14, 2010 at 4:01 pm

    [...] This post was mentioned on Twitter by wduffy, Caspar Kleijne. Caspar Kleijne said: RT @wduffy: New blog post, http://www.wduffy.co.uk/blog/c-literal-types/ – Just a little quick helpful post this one. #csharp #aspnet [...]

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