Re: How to know the size of array


manochavishal@xxxxxxxxx wrote:
Hi,

I have a question.

How can i know the size of array when it is passed to a function.

You can't, unless:

a) you pass it as an extra parameter
b) last element of your array is a "sentinel" value so you can
determine it at run-time (like C strings which are zero terminated).

For Example i have this code:

#include <stdio.h>
#include <stdlib.h>

void foo(int * array);

Try:

void foo(int *array, size_t len);


int main(void)
{
int n=5;
int array[n];

Not allowed in C90. Try:

#define ARRAY_SIZE 5
int array[ARRAY_SIZE];


foo(array);

foo(array, sizeof array / sizeof array[0]);


}

void foo(int * array)

void foo(int *array, size_t len)

{

Now the array size is in `len`.


/*Here how can i know the size of array without passing it explicitly*/
}

.

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