C interview 24 (pointer) define a double array with 20 elements a

24. ( The pointer ) Define a containing 20 An element of double Type of the array a, Define a pointer variable ptrDouble Point to the first address of the array , Then assign values to each element of the array through the pointer variable （ Equal to the subscript value times 3.2+1.5）. Next, let the pointer point to the array a Of a[10], Find the sum of all the following elements from this element
    requirement ：
    Output requirements ：1） Output all elements of the array ;2） Output the result obtained above 10 The sum of the elements ;
    Programming requirements ： In addition to defining arrays a Outside , Program about arrays a All operations of must pass through pointer variables ptrDouble To achieve .

void ff(int *arr,int len)
{ 
    
    int *ptrDouble=arr