From 22ff1db8a76c7047b61a424ae1fa5f43697fcb34 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@mit.edu>
Date: Wed, 20 Oct 2010 06:46:52 -0400
Subject: initial check-in of arduino docs in RST format (converted using
 wget+pandoc)

---
 docs/source/arduino/float.rst | 88 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 docs/source/arduino/float.rst

(limited to 'docs/source/arduino/float.rst')

diff --git a/docs/source/arduino/float.rst b/docs/source/arduino/float.rst
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+.. _arduino-float:
+
+float
+=====
+
+Description
+-----------
+
+Datatype for floating-point numbers, a number that has a decimal
+point. Floating-point numbers are often used to approximate analog
+and continuous values because they have greater resolution than
+integers. Floating-point numbers can be as large as 3.4028235E+38
+and as low as -3.4028235E+38. They are stored as 32 bits (4 bytes)
+of information.
+
+
+
+Floats have only 6-7 decimal digits of precision. That means the
+total number of digits, not the number to the right of the decimal
+point. Unlike other platforms, where you can get more precision by
+using a double (e.g. up to 15 digits), on the Arduino, double is
+the same size as float.
+
+
+
+Floating point numbers are not exact, and may yield strange results
+when compared. For example ``6.0 / 3.0`` may not equal ``2.0``. You
+should instead check that the absolute value of the difference
+between the numbers is less than some small number.
+
+
+
+Floating point math is also much slower than integer math in
+performing calculations, so should be avoided if, for example, a
+loop has to run at top speed for a critical timing function.
+Programmers often go to some lengths to convert floating point
+calculations to integer math to increase speed.
+
+
+
+Examples
+--------
+
+::
+
+        float myfloat;
+        float sensorCalbrate = 1.117;
+
+
+
+Syntax
+------
+
+::
+
+        float var = val;
+
+
+
+
+-  var - your float variable name
+-  val - the value you assign to that variable
+
+
+
+Example Code
+------------
+
+::
+
+       int x;
+       int y;
+       float z;
+    
+       x = 1;
+       y = x / 2;            // y now contains 0, ints can't hold fractions
+       z = (float)x / 2.0;   // z now contains .5 (you have to use 2.0, not 2)
+
+
+
+See Also
+--------
+
+
+-  `int <http://arduino.cc/en/Reference/Int>`_
+-  `double <http://arduino.cc/en/Reference/Double>`_
+-  `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_
+
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