Question

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“static const” vs “#define” in C

My first thought is that this is implied, but is there ever a reason why you would use const instead of #define?

If you set a global variable, why would you ever want to change it, and wouldn’t you want to protect it globally as well?

Answer 1

Const usually replaces #define

#define is a pre-processor macro that can do textual replacement. You can use it to define a constant or a macro or do all sorts of other things.

const is a type-safe way to define a compile-time constant

These two mechanisms occur at different times in the compilation process, but in general, const was created to rectify the problems of #define.

I’ve rarely seen people do something like

#define CONSTINT  const int

but it is legal.