Thread: Arrays and functions

In C, arrays are 0-based. That is, int array[5] would be indexed from array[0] to array[4]. Your function returns a value that is off the end of the array, not the whole array -- and not that you can return an array from a function anyway.

You cannot return an array from a function, especially a local array, but then again, you're not attempting to in the code.

I see several problems with your get_values() function; the reason that you're getting 0 all the time is that, when the for loop completes, the variable i has a value of 6, so you're attempting to return values[6], which is an error in itself since the array has only 5 elements, numbered from 0 through 4. Since the compiler is not inserting code to range check the array access, and since the array is declared as an "automatic", and is therefore on the stack, you're not getting an exception, but you're storing a value over top of whatever happens to have been on the stack following the last element of your array, and returning a float sized bit of data from the stack following that.

I hope this helps put you on the right path.

Yes and no. No, you can't return an array. Yes, you can return a pointer to a static array. You can also wrap the array in a structure, use that, and return that. Or, you could dynamically allocate an "array" and return it. But no, you can't just:

Code:

int [] function( void )
{
    int arrray[ SOMESIZE ];
    ...
    return array;
}

Can't do that.


Quzah.

Originally Posted by mikefountain

cheers guys, so mistakes aside, it isnt possible to return the array anyway?

Usually you pass a pointer to the first element and the size of the array.

Code:

float *get_values(float *values, int size)
{
   int i;
   for ( i = 0; i < size; ++i )
   {
      /* ... */
   }
   return values;
}

Whether or not you choose to return anything is up to you.