https://code-reference.com/ 2026-05-18T16:47:59+02:00 https://code-reference.com/ https://code-reference.com/ttps://code-reference.com/lib/tpl/dokuwiki/images/favicon.ico text/html 2024-02-16T01:04:13+02:00 https://code-reference.com/arduino/variable_scope_and_qualifiers/const?rev=1708041853&do=diff The const keyword stands for constant. It is a variable qualifier that modifies the behavior of the variable, making a variable ”read-only”. This means that the variable can be used just as any other variable of its type, but its value cannot be changed. You will get a compiler error if you try to assign a value to a const variable. text/html 2024-02-16T01:04:13+02:00 https://code-reference.com/arduino/variable_scope_and_qualifiers/scope?rev=1708041853&do=diff Variables in the C programming language, which Arduino uses, have a property called scope. This is in contrast to languages such as BASIC where every variable is a global variable. A global variable is one that can be seen by every function in a program. Local variables are only visible to the function in which they are declared. In the Arduino environment, any variable declared outside of a function (e.g. setup(), loop(), etc. ), is a global variable. text/html 2024-02-16T01:04:13+02:00 https://code-reference.com/arduino/variable_scope_and_qualifiers/static?rev=1708041853&do=diff The static keyword is used to create variables that are visible to only one function. However unlike local variables that get created and destroyed every time a function is called, static variables persist beyond the function call, preserving their data between function calls. text/html 2013-02-15T20:47:55+02:00 https://code-reference.com/arduino/variable_scope_and_qualifiers/variabledeclaration?rev=1360957675&do=diff A variable is a way of naming and storing a value for later use by the program, such as data from a sensor or an intermediate value used in a calculation. Declaring Variables Before they are used, all variables have to be declared. Declaring a variable means defining its type, and optionally, setting an initial value (initializing the variable). Variables do not have to be initialized (assigned a value) when they are declared, but it is often useful. text/html 2024-02-16T01:04:13+02:00 https://code-reference.com/arduino/variable_scope_and_qualifiers/volatile?rev=1708041853&do=diff volatile is a keyword known as a variable qualifier, it is usually used before the datatype of a variable, to modify the way in which the compiler and subsequent program treats the variable. Declaring a variable volatile is a directive to the compiler. The compiler is software which translates your C/C++ code into the machine code, which are the real instructions for the Atmega chip in the Arduino.