14. Array as Function Argument

#include <iostream>
using namespace std;
void foo( double dbls[] )
{
    cout
        << "in foo() size of dbls is "
        << sizeof( dbls )
        << '\n'
        ;
}
int main()
{
    double dummy[ 4 ] = { 0 };
    cout
        << "in main() size of dummy is "
        << sizeof(dummy)
        << '\n'
        ;
    foo( dummy );
    return 0;
}
/* Program output:
in main() size of dummy is 32
in foo() size of dbls is 4
*/

The size of an array is not available to the called function.

No matter what is the array type, function argument is simply a constant address of the initial element of the array.

Array differs from all other C++ types in such way that array is not (and cannot be) passed to a function by value!