Basic knowledge of C + +

1

In C + +, arrays are not allowed as return values for functions.

int [] someFunction (); Illegal

To implement a function that returns an array, returns a pointer to the type of the corresponding array

you must return a pointer to the array base type and has the pointer point to the array. So, the function declaration would is as follows: 
 int* someFunction ();//legal

int* doubler (int a[], int size)
{
int* temp = new Int[size];
for (int i =0; i < size; i++)
Temp[i] = 2*a[i];
return temp;
}

Call

int a[] = {1, 2, 3, 4, 5};
int* b;
b = Doubler (A, 5);

Delete[] B

Basic knowledge of C + +