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| diff --git a/docs/source/arduino/if.rst b/docs/source/arduino/if.rst deleted file mode 100644 index d75f6d3..0000000 --- a/docs/source/arduino/if.rst +++ /dev/null @@ -1,95 +0,0 @@ -.. _arduino-if: - -if (conditional) and ==, !=, <, > (comparison operators) -======================================================== - -**``if``**, which is used in conjunction with a comparison -operator, tests whether a certain condition has been reached, such -as an input being above a certain number. The format for an if test -is: - - - -:: - -    if (someVariable > 50) -    { -      // do something here -    } - - - -The program tests to see if someVariable is greater than 50. If it -is, the program takes a particular action. Put another way, if the -statement in parentheses is true, the statements inside the -brackets are run. If not, the program skips over the code. - - - -The brackets may be omitted after an *if* statement. If this is -done, the next line (defined by the semicolon) becomes the only -conditional statement. - -:: - -     -    if (x > 120) digitalWrite(LEDpin, HIGH);  -     -    if (x > 120) -    digitalWrite(LEDpin, HIGH);  -     -    if (x > 120){ digitalWrite(LEDpin, HIGH); }  -     -    if (x > 120){  -      digitalWrite(LEDpin1, HIGH); -      digitalWrite(LEDpin2, HIGH);  -    }                                 // all are correct - - - -The statements being evaluated inside the parentheses require the -use of one or more operators: - - - -Comparison Operators: -~~~~~~~~~~~~~~~~~~~~~ - -:: - -     x == y (x is equal to y) -     x != y (x is not equal to y) -     x <  y (x is less than y)   -     x >  y (x is greater than y)  -     x <= y (x is less than or equal to y)  -     x >= y (x is greater than or equal to y) - - - -Warning: --------- - -Beware of accidentally using the single equal sign -(e.g.``if (x = 10)`` ). 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 -`assignment operator <http://arduino.cc/en/Reference/Assignment>`_), -so x now contains 10. Then the 'if' conditional evaluates 10, which -always evaluates to TRUE, since any non-zero number evaluates to -TRUE. Consequently, ``if (x = 10)`` will always evaluate to TRUE, -which is not the desired result when using an 'if' statement. -Additionally, the variable x will be set to 10, which is also not a -desired action. - - - -**if** can also be part of a branching control structure using the -`if...else <http://arduino.cc/en/Reference/Else>`_] construction. | 
