How to get the number of elements of a C-array like this?

Question

I have a C-array like this:

double arr[] = {
    0.0,    0.1, 0.2, 0.5,
    0.1,    0.2, 0.3, 0.4,
    0.2,    0.0, 0.1, 0.3
};

Is it safe to get the number of elements like this?

int numElements = sizeof(arr)/sizeof(arr[0]);

Or is there a better way?

Remember this will not work for dynamic arrays, I also [explain how `sizeof(arr)/sizeof(arr[0])` works/meaning](http://stackoverflow.com/questions/18009725/weird-behavior-when-printing-array-in-c/18009736#18009736) — Grijesh Chauhan, Aug 07 '13 at 14:25

score 5 · Answer 1 · answered Aug 07 '13 at 12:06

5

This is the best way. Even it is suggested in C programming book by Dennis ritchie.

answered Aug 07 '13 at 12:06

user2550754

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score 4 · Accepted Answer · edited May 23 '17 at 12:23

4

this is a safe way and if you'll look at other question about size of array you'll find this as one of the most common suggestions

and so on.

actually in the last one the suggestion is to do

#define ARRAY_SIZE( array ) sizeof( array ) / sizeof( array[0] )

edited May 23 '17 at 12:23

Community

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answered Aug 07 '13 at 12:04

No Idea For Name

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score 2 · Answer 3 · answered Aug 07 '13 at 12:05

2

I don't know of any other way to do this, since you don't have a size.

It is reliable, yes.

answered Aug 07 '13 at 12:05

Tony The Lion

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score 2 · Answer 4 · answered Aug 07 '13 at 12:08

2

There are no other better way according to my knowledge, there are no problem in this one.
In java, there are jagged arrays. If it's also in c, then your thought may be correct.

answered Aug 07 '13 at 12:08

Govind Balaji

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How to get the number of elements of a C-array like this?

4 Answers4