Can the sizeof operator be used to tell the size of an array passed to a function?

No. There�s no way to tell, at runtime, how many elements are in an array parameter just by looking at the array parameter itself. Remember, passing an array to a function is exactly the same as passing a pointer to the first element.

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Mar 6th, 2005
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kiran

May 8th, 2007

Yes, the sizeof operator can tell the size of the array.
It gives the number of bytes reserved for that array.

yba

Jul 9th, 2007

The comment is incorrect, the original answer is correct.

In C, passing an array as a parameter does not pass any information about how many elements are in the array. sizeof() can tell you the size of the pointer, the size of the type it points to, but it has no way to tell you how many bytes are occupied by the entire array from inside the function.

Try writing code to do it. If sizeof() is confusing, add code inside the function to do array bounds checking, using only the array parameter, and see how far you get.