Consider the following data field and incomplete integer array sum such that for all $i,$ sum $[i]$ is

arr$[0]+$arr$[1]+$dots$+$arr$[i]$

For instance, if arr contains the values $,\{1,5,6,9\}.$

private int$[]$ arr;

public int$[]$ partialSum$()$

$\{$

int$[]$ sum $=$ new int$[$arr$.$length$]$;

for $($int $j=0$;$j$ sum.length;

${\displaystyle \underset{?}{\overset{?}{}}}[j]=0$;

$/*$ missing code $*/$

return sum;

$\}$

e following two implementations of $\frac{?}{?}**$ missi intended.

Implementation $1_{?}$

Implementation $2$