Question

Use java. Must use streams also but not the max or some other functions noted in the directions.

To clarify, you MUST USE STREAMS.

Answer 1

Hi, below is the complete program ReadFromFile.java along with Man class. As instructed, None of the Stream APIs re used in the program. In fact, I have used Java.nio.file.Files class to read from the file and store it in list. Prograam is very simple and I have also place comments wherever required. I have also attached input.txt file and the output of the program for reference .

ReadFromFile.java

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

//Class to read From a File and Store the contents in a List
public class ReadFromFile {

List<String> list = null;
        int count;                      //To count total numbers in the file
        int uniqueNumbers;      //To count total number of unique numbers in the file
        int maxLength;          //To indicate length of longest line
        int sumOfEven;          //To indicate sum of all even numbers
        boolean areAllEven;     //Boolean to check if all numbers are even or not
        
        public ReadFromFile() {
                this.list = new ArrayList<String>();
                this.count = 0;
                this.uniqueNumbers = 0;
                this.maxLength = 0;
                this.sumOfEven = 0;
                this.areAllEven = true;
        }

        /* Method to read a file line by line
         * Parameters: File object Return Type: Arrylist
         * Uses readAllLines method of Java.nio.file.Files class to read from 
         * a file whose path is given as parameter and stores the contents in a list
         */
        public ArrayList<String> read(File F){
                try {
                        list = Files.readAllLines(Paths.get(F.getAbsolutePath()), StandardCharsets.UTF_8);
                } catch (IOException e) {
                        e.printStackTrace();
                }
                
                //Set to store unique numbers. If duplicates are occurring they wont 
                //be stored in the Set, so Set will contain unique numbers
                //Which can be used to count number of Unique numbers in the file 
                Set<String> uniqueSet = new HashSet<>();
                for (String string : list) {
                        //For each line, if length is less than maxLength 
                        //store the length of line in maxLength
                        if(maxLength < string.length())
                                maxLength = string.length();
                        
                        //Split the numbers separated by , and count total numbers
                        String[] numbers = string.split(",");
                        count += numbers.length;
                        
                        for (String number : numbers) {
                                //add each number to set
                                uniqueSet.add(number);
                                int num = Integer.parseInt(number);
                                
                                //If number is not even set areAllEven to flse
                                //else add the even number to sumOfEven
                                if(num % 2 != 0)
                                        areAllEven = false;
                                else
                                        sumOfEven += num;
                        }
                }
                uniqueNumbers = uniqueSet.size();
                return (ArrayList<String>) list;          //Return ArrayList
        }
        public List<String> getList() {
                return list;
        }

        public int getCount() {
                return count;
        }

        public int getUniqueNumbers() {
                return uniqueNumbers;
        }

        public int getMaxLength() {
                return maxLength;
        }

        public int getSumOfEven() {
                return sumOfEven;
        }

        public boolean isAreAllEven() {
                return areAllEven;
        }
}

Reader.java(Main Class)

import java.io.File;
import java.util.ArrayList;

public class Reader {

public static void main(String[] args) {
                ReadFromFile readFromFile = new ReadFromFile();
                File file = new File("input.txt");
                ArrayList<String> list = readFromFile.read(file);
                
                System.out.println("Total Numbers in File= " + readFromFile.getCount());
                System.out.println("Total Number of Unique Numbers in File= " + readFromFile.getUniqueNumbers());
                System.out.println("Length of Longest Line= " + readFromFile.getMaxLength());
                System.out.println("Sum of Even Numbers= " + readFromFile.getSumOfEven());
                System.out.println("Are All Elements Even? " + readFromFile.isAreAllEven());
                
                System.out.println("Contents of the File: ");
                System.out.println(list.toString());
        }

}

input.txt

10,64,58,69,6,15,56,548,85,65
20,52,15,52,36,7,26,4
33,12,67,369,63,21,76,7
36,23,153,463,5,4,62,12,33
2,45,177,4,63,78,41
12,36,47,63,5,99,455,89,12,45,36
24,1,30,-2,96,47,25,36

Program Output:

Total Numbers in File= 61
Total Number of Unique Numbers in File= 43
Length of Longest Line= 32
Sum of Even Numbers= 1498
Are All Elements Even? false
Contents of the File: 
[10,64,58,69,6,15,56,548,85,65, 20,52,15,52,36,7,26,4, 33,12,67,369,63,21,76,7, 36,23,153,463,5,4,62,12,33, 2,45,177,4,63,78,41, 12,36,47,63,5,99,455,89,12,45,36, 24,1,30,-2,96,47,25,36]