Question

Part B: Java Programming Problems. Choose 2 of the following problems. Each solution is worth 20 marks. You are expected to use comments in your code. Marks will be deducted for incorrect brackets, syntax etc, so be careful as possible (40 marks). 1. Create a new program that: • Reads a sentence from a file; Writes the sentence to another file in reverse; and • Prints a message to the user in a JOptionPane message box when finished. 2. Write a program that: Allows the user to enter ten numbers from the keyboard; Removes any duplicate numbers (numbers that are the same); and • Prints top 5 numbers from highest to lowest. 3. Create a new program that: • Counts the number of lines and the number of words in a text file; and • Prints the number of lines and the number of words to the terminal.

Answer 1

1) Java Program to copy Sentence from file to another file

original.txt

- 0 x original - Notepad File Edit Format View This is a Sentence Help In 1, Col 19 100% Windows (CRLF) UTF-8

CODE

import java.io.*;
import java.io.FileReader;
import javax.swing.*;
public class Main
{
   // Function to reverse String
    public static String reverse(String sentence)
    {
        if (sentence.isEmpty()) {
           return sentence;
        }
        return reverse(sentence.substring(1)) + sentence.charAt(0);
    }
   public static void main(String[] args) throws IOException{
       // Reading a File from given path
        FileReader fr=new FileReader(new File("C:\\Users\\ChiTTi ThaLLI\\Desktop\\original.txt"));
        // Creating BufferReader to Read data from file
        BufferedReader br = new BufferedReader(fr);
        String s=br.readLine(); // Reading sentence from file
        br.close(); // Closing Buffered Reader
        fr.close(); // Closing FileReader
        // Creating FileWriter to create and write to a file
        FileWriter fw=new FileWriter("C:\\Users\\ChiTTi ThaLLI\\Desktop\\copy.txt");
        String reversed=reverse(s); // Calling function to reverse string, storing to variable
        fw.write(reversed);        // Writing reversed string to file
        fw.close();                   // Closing FileWriter
        JFrame f=new JFrame();       // Creating JFrame to display message
        JOptionPane.showMessageDialog(f,"Successfully Copied"); // Displaying message
        System.exit(1);               // Terminating Java Program
   }
}

OUTPUT

Message 0 Successfully copied OK

copy.txt

copy - Notepad File Edit Format View ecnetnes a si siht Help In 1, Col1 100% Windows (CRLF) UTF-8

CODE in EDITOR

Main.java X 10 import java.io.*; 2 import java.io.FileReader; 3 import javax.swing. *; 4 public class Main 5 { // Function to reverse String public static String reverse(String sentence) if (sentence.isEmpty() { return sentence; return reverse( sentence.substring(1)) + sentence.charAt(0); public static void main(String[] args) throws IOException{ // Reading a File from given path FileReader fr=new FileReader(new File("C:\\Users\\Chiti // Creating BufferReader to Read data from file BufferedReader br = new BufferedReader(fr); String s=br.readLine(); // Reading sentence from file br.close(); // Closing Buffered Reader fr.close(); // Closing FileReader // Creating FileWriter to create and write to a file FileWriter fw=new FileWriter("C:\\Users\\Chilti ThalLI\Desktop\\copy.txt"); String reversed=reverse(); // Calling function to reverse string, storing to variable fw.write(reversed); rsed string to file fw.close(); // Closing FileWriter JFrame f=new JFrame(); // Creating JFrame to display message JOptionPane.showMessageDialog(f, "Successfully copied"); // Displaying message System.exit(1); // Terminating Java Program 32

2) Java program to remove duplicates from array and print top 5 from array

CODE

import java.util.Scanner;
import java.util.Arrays;
public class Duplicate {

   @SuppressWarnings("resource")
   public static void main(String[] args) {
       // Scanner class instance read user input
       Scanner scan=new Scanner(System.in);
       int array[]=new int[10];   // Creating array of size 10
       int n = array.length;       // Getting array size
       for(int i=0;i<10;i++) {
           array[i]=scan.nextInt();// Scanning 10 values from user
       }
       System.out.print("Original Array : ");
       for(int i=0;i<10;i++) {
           System.out.print(array[i]+" ");
       }
       System.out.println();
       Arrays.sort(array);
       System.out.print("Sorted Array : ");
       for(int i=0;i<10;i++) {
           System.out.print(array[i]+" ");
       }
       System.out.println();
       n = removeDuplicates(array, n); // Calling function to get nonduplicate values index
       int[] array2=new int[n];       // Creating new array to store non duplicate values
       for(int i=0;i<n;i++) {
           array2[i]=array[n-i-1];
       }
       System.out.print("Array Without Duplicates : ");
       for(int i=0;i<n;i++) {
           System.out.print(array2[i]+" ");
       }
       System.out.println();
       int maxim=0;
       if(array2.length>4) {
           maxim=5;
       }else {
           maxim=array2.length;
       }
       System.out.print("Top 5 numbers from Highest to Lowest : ");
       for(int i=0;i<maxim;i++) {
           System.out.print(array2[i]+" ");
       }
       System.out.println();
   }
   // Function to remove duplicate elements
    // This function returns new size of modified
    // array.
    static int removeDuplicates(int arr[], int n)
    {
        if (n == 0 || n == 1)
            return n;
     
        // To store index of next unique element
        int j = 0;
     
        // Doing same as done in Method 1
        // Just maintaining another updated index i.e. j
        for (int i = 0; i < n-1; i++)
            if (arr[i] != arr[i+1])
                arr[j++] = arr[i];
     
        arr[j++] = arr[n-1];
     
        return j;
    }

}

OUTPUT in CONSOLE

** E * ? @- pre @ Console X <terminated> Duplicate [Java Application] C:\Program FilesVava\jdk-13\bin\javaw.exe (20-Feb-2020, 3:18:37 pm 3 1 2 3 4 6 5 7 6 2 þriginal Array : 3 1 2 3 4 6 5 7 6 2 Sorted Array : 1 2 2 3 3 4 5 6 67 Array Without Duplicates : 7 6 5 4 3 2 1 Top 5 numbers from Highest to Lowest : 7 6 5 4 3

CODE in EDITOR

Duplicate.java X 10 import java.util.Scanner; 2 import java.util.Arrays; 3 public class Duplicate ! @SuppressWarnings ("resource") public static void main(String[] args) { // Scanner class instance read user input Scanner scan=new Scanner(System.in); int array[]=new int[10]; // Creating array of size 10 int n = array.length; // Getting array size for(int i=0; i<10; i++) { array[i]=scan.nextInt(); // Scanning 10 values from user System.out.print("Original Array : "); for(int i=0;i<10; i++) { System.out.print(array[i]+" "); System.out.println(); Arrays. sort(array); System.out.print("Sorted Array : "); for(int i=0;i<10; i++) { System.out.print(array[i]+" "); System.out.println(); n = removeDuplicates(array, n); // Calling function to get nonduplicate values index int[] array2=new int[n]; // Creating new array to store non duplicate values for(int i=0;i<n;i++) { array2[i]=array[n-i-1]; System.out.print("Array Without Duplicates : "); for(int i=0;i<n;i++) { System.out.print(array[i]+" "); System.out.println(); int maxim=0; if(array2.length>4) { maxim=5; }else { maxim=array2.length;

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3) Java program to count no.of Lines and no.of Words in a file

counting.txt

Help counting - Notepad File Edit Format View This is text file this file contains 4 lines and 12 words In 1, Col1 100% Windows (CRLF) UTF-8

CODE

import java.io.*;

// Class to count lines and words in a file
public class Couting {

   public static void main(String[] args) throws IOException{
       // Creating a FileReader instance with given file path
       FileReader fr=new FileReader(new File("C:\\Users\\ChiTTi ThaLLI\\Desktop\\counting.txt"));
       // Creating BufferedReader to read data from file
       BufferedReader br = new BufferedReader(fr);
       String s;                               // String to store data
       int lines_count=0;                       // Variable to store lines count
       int word_count=0;                       // Variable to store word count
       while((s = br.readLine()) != null){       // Loop until reaches END OF FILE
           lines_count=lines_count+1;            // Incrementing Lines count
           if(!(s.equals("")))                // Checking line is not empty
            {
               String[] words = s.split(" ");   // Splitting string and store words into array
               word_count=word_count+words.length; // Incrementing word count by size of array above
            }
       }
       br.close();   // Closing bufferedreader
       fr.close(); // CLosing file reader
      
       // Printing Lines count and Word count
       System.out.println("Lines count in File: "+lines_count);
       System.out.println("Word count in File: "+word_count);
   }

}

OUTPUT in CONSOLE

Console X <terminated> Couting [Java Application] C:\Program FilesVava Lines count in File: 4 Word count in File: 12

CODE IN EDITOR

Couting.java X 1 import java.io.*; 3 // Class to count lines and words in a file 4 public class Couting { public static void main(String[] args) throws IOException{ // Creating a FileReader instance with given file path FileReader fr=new FileReader(new File("C:\\Users\\Chitti ThaLLI\\Desktop\\counting.txt")); // Creating BufferedReader to read data from file BufferedReader br = new BufferedReader(fr); String s; // String to store data int lines_count=0; // Variable to store lines count int word_count=0; // Variable to store word count while((s = br.readLine()) != null){ // Loop until reaches END OF FILE lines_count=lines_count+1; // Incrementing Lines count if(!(s.equals(""))) // Checking line is not empty String[] words = s.split(" "); // Splitting string and store words into array word_count=word_count+words.length; // Incrementing word count by size of array above br.close(); // Closing bufferedreader fr.close(); // Closing file reader // Printing Lines count and Word count System.out.println("Lines count in File: "+lines_count); System.out.println("Word count in File: "+word_count);

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