#define MY_INT VS const int MY_INT

Question

Possible Duplicate:
“static const” vs “#define” in c

When I do this :

#define WEEKDAYS 7

and that :

const int WEEKDAYS = 7;

Any difference between them ? seems that both do the same thing - sets a constant value for future usage within the code .

You've tagged this as both C and C++. The answers are somewhat different for the different languages. — , Aug 25 '12 at 16:29
It'd be easier to say **NEVER** tag a question both C and C++. — Jeff Mercado, Aug 25 '12 at 16:31
@JeffMercado It'd be easier, but it'd be wrong. :) The easiest example is a question asking specifically about one of the differences between C and C++ (I recall a recent question asking why `sizeof('a')` differs from `sizeof(char)` in C, but not in C++) — , Aug 25 '12 at 16:33
@hvd: What that's a question about specific differences between the two languages. What I really meant was tagging with both tags on a question that's not specifically looking for a comparison of the languages. But whatever, it's still going to happen whether we like it or not. — Jeff Mercado, Aug 25 '12 at 16:38
Agreed. FWIW, this is now closed as a duplicate of the question for C, but as ron has removed the C tag (thanks), http://stackoverflow.com/questions/1637332/static-const-vs-define (linked in the other question) may be useful to mention here. — , Aug 25 '12 at 16:42

score 7 · Accepted Answer · answered Aug 25 '12 at 16:30

7

#define WEEKDAYS 7

void f() {
    int WEEKDAYS = 3; // error
}

const int WEEKDAYS_CONST = 7;

void g() {
    int WEEKDAYS_CONST = 3; // okay: local scope for WEEKDAYS_CONST
}

answered Aug 25 '12 at 16:30

Pete Becker

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score 2 · Answer 2 · answered Aug 25 '12 at 16:29

2

#define WEEKDAYS 7

Replaces all occurrence of the word WEEKDAYS in your source file with the digit 7.

const int WEEKDAYS = 7;

Defines an actual constant represented by 7 that you can access in your code.

answered Aug 25 '12 at 16:29

Qiau

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3
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#define MY_INT VS const int MY_INT

2 Answers2