SHOW ALL YOUR WORK. REMEMBER THAT PROGRAM SEGMENTS ARE TO BE WRITTEN IN JAVA.

Assume that the classes listed in the Java Quick Reference have been imported where appropriate.

Unless otherwise noted in the question, assume that parameters in method calls are not nu$11$ and that

methods are called only when their preconditions are satisfied.

In writing solutions for each question, you may use any of the accessible methods that are listed in

classes defined in that question. Writing significant amounts of code that can be replaced by a call to one

of these methods will not receive full credit.

This question involves manipulating a two$-$dimensional array of integers. You will write two static methods

of the ArrayResizer class, which is shown below.

public class ArrayResizer

$/*$ Returns true if and only if every value in row $r$ of array$2$D

is non$-$zero.

Precondition: $r$ is a valid row index in array$2$D$.$

Postcondition: array$2$D is unchanged.

public static boolean isNonzeroRow$($int$[][]$ array$2$D$,$ int $r)$

$(/$t to be implemented in part $($a$)*/)$

$/*$ Returns the number of rows in array $2D$ that contain all

non$-$zero values.

Postcondition: array$2$D is unchanged.

public static int numNonzeroRows $($int$[][]$ array$2$D$)$

$(/*$ implementation not shown $*/\}$

$/*$ Returns a new, possibly smaller, two$-$dimensional array that

contains only rows from array$2$D with no zeros, as described

in part $($b$).$

Precondition: array$2$D contains at least one column

and at least one row with no zeros.

Postcondition: array$2$D is unchanged.

public static int$[][]$ resize$($int$[][]$ array$2$D$)$

$(/*$ to be implemented in part $($b$)*/\}$

$($a$)$ Write the method isNonzeroRow, which returns true if and only if all elements in row $r$ of a two$-$

dimensional array array $2D$ are not equal to zero.

For example, consider the following statement, which initializes a two$-$dimensional array.

int$[][]$ arr $=\{\{2,1,0\},$

$\{1,3,2\},$

$0,0,0\},$

$\{4,5,6\}$

Sample calls to isNonzeroRow are shown below.

Complete the isNonzeroRow method.

$($b$)$ Write the method resize, which returns a new two$-$dimensional array containing only rows from

array $2$ D with all non$-$zero values. The elements in the new array should appear in the same order as the order in

which they appeared in the original array.

The following code segment initializes a two$-$dimensional array and calls the resize method.

int$[][]$ arr $=\{\{2,1,0\},$

$\{1,3,2\},$

$\{0,0,0\},$

$\{4,5,6\}\}$;

int$[][]$ smaller $=$ ArrayResizer.resize$(arr)$;

When the code segment completes, the following will be the contents of smaller.

$\{\{1,3,2\},\{4,5,6\}\}$

A helper method, numNonzeroRows, has been provided for you. The method returns the number of rows in its two$-$

dimensional array parameter that contain no zero values.

Complete the resize method. Assume that isNonzeroRow works as specified, regardless of what you wrote in

part $($a$).$ You must use numNonZeroRows and isNonZeroRow appropriately to receive full credit.

$/*$ Returns a new, possibly smaller, two$-$dimensional array that

contains only rows from array$2$D with no zeros, as described

in part $($b$).$

Precondition: array$2$D contains at least one column

and at least one row with no zeros.

Postcondition: array$2$D is unchanged.

public static int$[][]$ resize$($int$[][]$ array$2$D$)$