Question

[10] Create a program called SelectionSort.java that implements the Selection Sort algorithm (The Art of Computer Programming - Donald Knuth). The algorithm is as follows: The program should be able to do the following: accepts one command line parameter. The parameter specifies the path to a text file containing the integers to be sorted. The structure of the file is as follows: There will be multiple lines in the file (number of lines unknown). Each line will contain multiple integers, separated by a single whitespace. reads the integers from the text file in part a into an array of integers. sort the integers in ascending order, and then prints out a sorted version of these integers, one per line. The implementation should follow the given the pseudo code/algorithm description.

Answer 1

import java.io.File;

import java.io.FileNotFoundException;

import java.util.ArrayList;

import java.util.Scanner;

public class SelectionSort {

public static void main(String[] args) throws FileNotFoundException {

//For array

ArrayList<Integer>array=new ArrayList<Integer>();

//If argument found

if(args.length>=1) {

//File path

Scanner sc=new Scanner(new File(args[0]));

//Loop until end

while(sc.hasNextLine()) {

//Read each line and add into array

String[] temp=sc.nextLine().split(" ");

for(int i=0;i<temp.length;i++) {

array.add(Integer.parseInt(temp[i]));

}

}

//Display array

System.out.println("Display array: ");

printArray(array);

System.out.println("\\Display array after sort: ");

sortArray(array);

printArray(array);

}

//If argument not found

else {

System.out.println("Argument not found!!!");

}

}

//Method to print array

public static void printArray(ArrayList<Integer>array) {

for(int i=0;i<array.size();i++) {

System.out.println(array.get(i));

}

}

//Method to sort array using straight selection sort

public static void sortArray(ArrayList<Integer>array) {

//Step1

for(int j=array.size()-1;j>=1;j--) {

int max=array.get(j);

int index=j;

//Step2

for(int k=j;k>=0;k--) {

if(max<array.get(k)) {

max=array.get(k);

index=k;

}

}

//Step3

array.set(index,array.get(j));

array.set(j,max);

}

}

}

Step-by-step explanation: