[Variable Scope & Qualifiers]
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
Constants defined with the
const keyword obey the rules of variable scoping that govern other variables. This, and the pitfalls of using
#define, makes the
const keyword a superior method for defining constants and is preferred over using
const float pi = 3.14; float x; // .... x = pi * 2; // it's fine to use consts in math pi = 7; // illegal - you can't write to (modify) a constant
You can use either
#define for creating numeric or string constants. For arrays, you will need to use
const. In general
const is preferred over
#define for defining constants.
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