CODEWITHSUNDEEP
c#typesfloating-pointdouble
user1063287
user1063287

Reputation: 10839

What are the actual ranges of floating point and double data types in C#?

I'm learning C# and trying to get a logical visual representation of the actual range of data types in C#.

I have moved through the integers and am now up to float and double data types.

  1. 8 bits (1 byte), sbyte, -128 to 127.
  2. 8 bits (1 byte), byte, 0 to 255.
  3. 16 bits (2 bytes), short, -32,768 to 32,767.
  4. 16 bits (2 bytes), ushort, 0 to 65535.
  5. 32 bits (4 bytes), int, -2,147,483,648 to 2,147,483,647.
  6. 32 bits (4 bytes), uint, 0 to 4,294,967,295.
  7. 64 bits (8 bytes), long, -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
  8. 64 bits (8 bytes), ulong, 0 to 18,446,744,073,709,551,615.

Here are the references to float and double data types sizes at msdn:

Float: http://msdn.microsoft.com/en-us/library/b1e65aza(v=vs.110).aspx

enter image description here

Double: http://msdn.microsoft.com/en-us/library/678hzkk9.aspx

enter image description here

So, trying to keep with the convention of specifiying the actual range of numbers as in the numbered list above, what do these two ranges actually represent?

Upvotes: 2

Views: 49143

Answers (2)

Eric Postpischil
Eric Postpischil

Reputation: 222234

The ranges are actually –infinity to +infinity.

The largest finite float is 340282346638528859811704183484516925440. This is 2128–2128–24.

The largest finite double is 179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368. This is 21024–21024–53.

Upvotes: 11

Eren Ersönmez
Eren Ersönmez

Reputation: 39085

The ranges are represented in "exponential format" for conciseness. For example, +1.7e+308 means 17 followed by 307 zeros:

1,700,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

So the exponential format is preferred for such large numbers. And the same goes for extremely small numbers.

Also, take a look at this reading by Jon Skeet.

Upvotes: 8

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