Overview

The goal of this first programming assignment is two$-$fold. First, to give you a basic

introduction to programming the algorithms discussed in class. Second, to give you a

chance to get comfortable with programming in Java for the more complicated

Assignments #$2$ and #$3$ to be released after the mid$-$term. Most of the pseudo$-$code

needed for this assignment is in the lecture slides or problem solutions on moodle.

Starter$/$Skeleton Code

This document is accompanied by starterCode.zip, which includes three java files,

described below. Each of these files contains a skeleton code to provide you a starter

point. Mainly just the class structure and comments.

matrixMul.java

This is the main java file for this assignment. It contains a single driver method. The

user inputs a single input, a number that defines the size n of$\text{'}$ a square matrix. Your

code must create two matrices "lefiMatrix" and "righ Matrix" filled with randomly

generated elements using randMatrix.java below. You then sort the rows in the

leftMatrix, as in every element in a row must be sorted like this

and sort the columns of "rightMatrix" as below

Note, only one row and column are highlighted but each is sorted.

Then you multiply the two matrices to create a third square matrix of size n$.$ You may

at your discretion add more methods if you think they optimize your code.

randMatrix.java

This class creates and holds a $2$D matrix object. This object is assigned random values

in the constructor which is called by the main function of matrixMul.java when the

object is created. This class also contains sortMat, that uses the array$-$sorting

algorithm from the sortAlg.java class below on the rows or columns of the matrix.

sortAlg.java

This class defines a sorting algorithm optimized for randomly generated arrays.

Implement the sorting algorithm that you think is optimal here. It is used by the

randMatrix class. It contains only two methods, a sortA method recursively sorts an

array, and a helper method to perform any external functions the algorithm may need.

These methods are static, so they do not require an instance of this class to be created

Bonus pro$-$hint: If you want to$,$ you can implement different sorting algorithms and

calculate the exact run$-$lime using System,nanoTime$(),$ you could test a few input

values of n to average run$-$time.

Output

The driver code matrixMul.java needs to print the following:

lefMatrix and rightMatrix with random numbers are initialized.

Sorted lef Matrix and rightMatrix after sorling as described above.

Final Matrix afler multiplication.

Additional print and exception handling of good code $($extra credit possibly???$)$:

Invalid input..what if the input is not an integer? What would you tell the user?

Edge cases what kind of edge cases you would warn your users against?$\text{'}($also

something to consider documenting in your code$)$ matrixMul.java

public class matrixMul

$\{$

$/*$

$*$ This driver creates two $2$D matrices of randMatrix class from the user input size

$*$ it then sorts left matrix rows and right matrix columns

$*$ then it multiplies left matrix with the right matrix and saves it as new $2$D matrix

$*$ prints: random left and right matrices, sorted left and right matrices, new matrix

$*/$

public static void main$($String$[]$ arr$)$

$\{$

int size $=$ Integer.parseInt$($args$[0])$;

$//$Implement rest of this method

$\}$

$\}$

randMatrix.java

public class randMatrix

$\{$

public int$[][]$ matrix ;

boolean sorted;

$/*$

$*$ Constructor used to build square matrix of size n$*$n and assign random value to each element in the matrix

$*/$

public static void randMatrix$($int n$)$

$\{$

$//$Implement this method

$\}$

$/*$

$*$ sorts matrix

$*$ input $-$ axisType $($ row or column $)$

$*/$

public static void sortMat$($axisType$)$

$\{$

$//$Implement this method

$\}$

$\}$

sortAlg.java

public class sortAl

$\{$

public static void sortA$($int$[]$ arr$)$

$\{$

$//$Implement this method

$\}$

private static int helper$(//$fill your input parameters$)$

$\{$

$//$Implement this method

$\}$

$\}$

$*$String$[]$ arr should be String$[]$ args$*$ in the matrixmul.java