Size of an array

[kreagan]

I know one method of finding the size of an array is:

[CODE=c]int x[5] = {0};
(sizeof (x) / sizeof *(x) )[/CODE]

But is there better looking way? For example, java can use array.length() or array.length. Is there anything like that in C?

[minkkp]

I know one method of finding the size of an array is:

[CODE=c]int x[5] = {0};
(sizeof (x) / sizeof *(x) )[/CODE]

But is there better looking way? For example, java can use array.length() or array.length. Is there anything like that in C?

in C.....say your string is lastName...i think you would enter lastName.Length
in C....
in c++ in think you would enter: cout <<lastName.leng th()<<endl;

[Savage]

in C.....say your string is lastName...i think you would enter lastName.Length
in C....
in c++ in think you would enter: cout <<lastName.leng th()<<endl;

C doesn't have string class.
And kreagen wonts to know for every type of array,not only of char type.

Kreagen,I'm not sure that there is another way.

Any specific reason to ask?


Savage

[kreagan]

C doesn't have string class.
And kreagen wonts to know for every type of array,not only of char type.

Kreagen,I'm not sure that there is another way.

Any specific reason to ask?
Savage

Ah, I thought so. I come from a java background. So when I write for loops, I always write it like:

[CODE=c]for ( i = 0; i < sizeof(x); i++)[/CODE]

Then I get that annoying "array out of bounds" fault. Old habits are hard to break. Plus

[CODE=c](sizeof (x) / sizeof *(x) )[/CODE]

just looks really ugly to me.

[Ganon11]

I simply pass an additional int value to any function that uses the array, and use that to indicate the size. Alternatively, you could write a function to determine the size of any array passed to it, and use that. But I agree, Java is much nicer in allowing array.length to be used.

[kreagan]

I simply pass an additional int value to any function that uses the array, and use that to indicate the size. Alternatively, you could write a function to determine the size of any array passed to it, and use that. But I agree, Java is much nicer in allowing array.length to be used.

Oooh! I can use a macro instead of a function! Thanks for the idea!

[weaknessforcats]

Oooh! I can use a macro instead of a function! Thanks for the idea!

Bad idea.

The number of elements in an array is determined by the number in the first index:
[code=c]
int array[5]; //5 elements
int array[5][6]; //5 elements
int array[5][6][7]; //5 elements
[/code]

The other indexes describe the elements. You will always be better off using a variable for the first index and then passing that variable and the array address to your functions.

The trick:

(sizeof (x) / sizeof *(x) )

does not work. The number of elements is the size of the array divided by the size of element 0 and not the size of the type stored in the array.

This is correct:
[code=c]
(sizeof (x) / sizeof (x[0]);
[/code]

And be aware that when this array is passed to a function, only the address is passed so sizeof(x) becomes the size of the address and you get 4.

Stick with a variable containing the number of elements.