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diff --git a/source/arduino/assignment.rst b/source/arduino/assignment.rst new file mode 100644 index 0000000..8b851e8 --- /dev/null +++ b/source/arduino/assignment.rst @@ -0,0 +1,63 @@ +.. highlight:: cpp + +.. _arduino-assignment: + += assignment operator (single equal sign) +========================================= + +Stores the value to the right of the equal sign in the variable to +the left of the equal sign. + + +The single equal sign in the C++ programming language is called the +assignment operator. It has a different meaning than in algebra +class where it indicated an equation or equality. The assignment +operator tells the microcontroller to evaluate whatever value or +expression is on the right side of the equal sign, and store it in +the variable to the left of the equal sign [#fgross]_. + + + +Example +------- + +:: + + int sensVal; // declare an integer variable named sensVal + senVal = analogRead(0); // store the (digitized) input voltage at analog pin 0 in SensVal + + + +Programming Tips +---------------- + +The variable on the left side of the assignment operator ( = sign ) +needs to be able to hold the value stored in it. If it is not large +enough to hold a value, the value stored in the variable will be +incorrect. + + + +Don't confuse the assignment operator [ = ] (single equal sign) +with the comparison operator [ == ] (double equal signs), which +evaluates whether two expressions are equal. + + + +See Also +-------- + + +- `if (comparison operators) <http://arduino.cc/en/Reference/If>`_ +- `char <http://arduino.cc/en/Reference/Char>`_ +- `int <http://arduino.cc/en/Reference/Int>`_ +- `long <http://arduino.cc/en/Reference/Long>`_ + + +.. rubric:: Footnotes + + Experienced C++ programmers know this to be an oversimplification + of what happens when the variable on the left hand side is an + object. See Richard Gillam's wonderful and scary `The Anatomy of + the Assignment Operator + <http://icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html>`_ |