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-.. highlight:: cpp
-
-.. _arduino-comparison:
-
-Comparison Operators
-====================
-
-The comparison operators ``==``, ``!=``, ``<``, ``>``, ``<=``, and
-``>=`` are used to compare two numbers. They are :ref:`true
-<arduino-constants-true>` when the comparison is true, and :ref:`false
-<arduino-constants-false>` otherwise. They are based on the symbols
-=, ≠, <, >, ≤, and ≥ from mathematics.
-
-Here are some examples, with their meaning in comments::
-
- // "eq" is true when x is equal to y
- bool eq = (x == y);
-
- // "neq" is true when x is different than y
- bool neq = (x != y);
-
- // "lt" is true when x is less than, but NOT equal to, y
- bool lt = (x < y);
-
- // "gt" is true when x is greater than, but NOT equal to, y
- bool gt = (x > y);
-
- // "lte" is true when x is less than or equal to y
- bool lte = (x <= y);
-
- // "gte" is true when x is greater than or equal to y
- bool gte = (x >= y);
-
-The parentheses are optional; they are present only for clarity. For
-example, the following two lines are the same::
-
- bool eq = x == y;
-
- bool eq = (x == y);
-
-Uses
-----
-
-Comparison operators, along with :ref:`boolean operators
-<arduino-boolean>`, are useful inside the conditionals of :ref:`if
-<arduino-if>` statements. Here's one example::
-
- if (x < 50) {
- // only execute these lines if x is less than 50
- SerialUSB.println("delaying:");
- SerialUSB.println(x);
- delay(x);
- }
-
-.. warning::
- Beware of accidentally using the single equal sign (``=``) when you
- meant to test if two numbers are equal (``==``). This is a common
- mistake inside of ``if`` statement conditionals, e.g.::
-
- // DON'T MAKE THIS MISTAKE
- if (x = 10) {
- // body
- }
-
- The single equal sign is the assignment operator, and sets x to 10
- (puts the value 10 into the variable x). Instead use the double equal
- sign (e.g. ``if (x == 10)``), which is the comparison operator, and
- tests *whether* x is equal to 10 or not. The latter statement is only
- true if x equals 10, but the former statement will always be true.
-
- This is because C evaluates the statement ``if (x=10)`` as follows: 10
- is assigned to x (remember that the single equal sign is the
- :ref:`assignment operator <arduino-assignment>`), so x now
- contains 10. Then the 'if' conditional evaluates 10, which evaluates
- to :ref:`true <arduino-constants-true>`, since any non-zero number
- evaluates to ``true``.
-
- Consequently, the conditional of an ``if`` statement like ``if (x =
- 10) {...}`` will always evaluate to ``true``, and the variable x
- will be set to 10, which is probably not what you meant.
-
- (This sometimes has uses, though, so just because an assignment
- appears within a conditional doesn't mean it's automatically wrong.
- Be careful to know what you mean.)
-
-
-.. include:: cc-attribution.txt \ No newline at end of file