Question

i have two classes namely Flight and Runway. Now i am trying to pass an array of these objects as parameter to a function.

void fun(Flight ptr1[],Runway ptr2[])
{
...
...
}

ptr1 should point to an array of Flight objects and ptr2 should point to an array of Runway objects.
Now inside this function fun() how do i access members of these classes. Also can i use ptr1++ or ptr2++ to move between the objects??
Also how would i be calling this func??something like this –

Flight array1[5];
Runway array2[2];
fun(array1,array2);

Answer 1

void fun(Flight ptr1[],Runway ptr2[])

is interpreted as

void fun(Flight *ptr1, Runway *ptr2)

This is called “decomposition,” and I think it’s rotten. It’s mainly a feature for backward compatibility with C. If you want pointers, specify pointers, not arrays, because pointers and arrays are different things.

You can also do

void fun(Flight (&arr1)[5], Runway (&arr2)[7])

Now the parameters remain arrays inside the function, not pointers, so ++ arr1 is illegal and sizeof arr1/sizeof arr1[0] is 5. The argument arrays when you call the function also must be the correct size, exactly 5 and 7 respectively. In this context, & means pass-by-reference, so the arrays are not copied when you call the function.

You can leverage the template system to generate a function for any size argument array, as well:

template< size_t NF, size_t NR >
void fun(Flight (&arr1)[NF], Runway (&arr2)[NR])

Such a template may be called with any-sized arrays, and NF and NR will be integral constants set to the proper sizes.