Infinity: Difference between revisions
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return std::numeric_limits<double>::max(); |
return std::numeric_limits<double>::max(); |
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=={{header|IDL}}== |
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IDL provides the standard IEEE values for _inf and _NaN in the !Values system structure: |
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print, !Values.f_infinity ;; for normal floats or |
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print, !Values.D_infinity ;; for doubles |
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=={{header|J}}== |
=={{header|J}}== |
Revision as of 23:22, 7 February 2008
You are encouraged to solve this task according to the task description, using any language you may know.
Write a function which tests if infinity is supported for floating point numbers (this step should be omitted for languages where the language specification already demands the existence of infinity, e.g. by demanding IEEE numbers), and if so, returns positive infinity. Otherwise, return the largest possible number.
For languages with several floating point types, use the type of the literal constant 1.0 as floating point type.
Ada
compiler: GNAT GPL 2007
with Ada.Text_Io; use Ada.Text_Io; with Ada.Float_Text_Io; use Ada.Float_Text_Io; procedure Infinities is F : Float := Float'Last; I : Float := F * 10.0; Ff : Float := Float'First; II : Float := FF * 10.0; begin Put(Item => F); New_Line; Put(Item => I); New_Line; Put(Item => Ff); New_Line; Put(Item => Ii); end Infinities;
Output:
3.40282E+38 +Inf******** -3.40282E+38 -Inf********
C++
#include <limits> double inf() { if (std::numeric_limits<double>::has_infinity) return std::numeric_limits<double>::infinity(); else return std::numeric_limits<double>::max(); }
IDL
IDL provides the standard IEEE values for _inf and _NaN in the !Values system structure:
print, !Values.f_infinity ;; for normal floats or print, !Values.D_infinity ;; for doubles
J
Positive infinity is produced by the primary constant function _:
It is also represented directly as a numeric value by an underscore, used alone.
Java
Java does not have a test for the existence of infinity, but it does have the concept in the Double class.
double infinity = Double.POSITIVE_INFINITY; //defined as 1.0/0.0 Double.isInfinite(infinity); //true
As a function:
public static double getInf(){ return Double.POSITIVE_INFINITY; }
The largest possible number in Java (without using the Big classes) is also in the Double class.
double biggestNumber = Double.MAX_VALUE;
Its value is (2-2-52)*21023 or 1.7976931348623157*10308 (a.k.a. "big"). Other number classes (Integer, Long, Float, Byte, and Short) have maximum values that can be accessed in the same way.