Difference between revisions of "Compute the number of elements in an array"
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==Implementations== | ==Implementations== | ||
===C/C++=== | ===C/C++=== | ||
| + | The trick to computing the number of elements in an array is to divide the total size of an array by the size of a given element. For example, if the total size of the array is 80 bytes and each element takes up 8 bytes, there must be 10 elements in the array. | ||
<pre> | <pre> | ||
sizeof(array) / sizeof(array[0]); | sizeof(array) / sizeof(array[0]); | ||
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#define NumElm(array) (sizeof(array) / sizeof((array)[0])) | #define NumElm(array) (sizeof(array) / sizeof((array)[0])) | ||
</pre> | </pre> | ||
| − | <b>Note</b>: | + | <b>Note</b>: this method will not work for arrays that are zero- or null-terminated (including strings). |
===Java=== | ===Java=== | ||
Revision as of 10:17, 3 July 2008
Implementations
C/C++
The trick to computing the number of elements in an array is to divide the total size of an array by the size of a given element. For example, if the total size of the array is 80 bytes and each element takes up 8 bytes, there must be 10 elements in the array.
sizeof(array) / sizeof(array[0]);
Ideally, you would put this into a macro as follows:
#define NumElm(array) (sizeof(array) / sizeof((array)[0]))
Note: this method will not work for arrays that are zero- or null-terminated (including strings).
Java
int[] myArray; myArray.length();
