Question

Create a program RandomFile.java that generates files with random numbers/characters.

You are required to write the following three methods in the class RandomFile:

​public static void randomBinaryFile(String fileName, int length)

​public static void randomNumberFile(String fileName, intlength)

​public static void randomCharFile(String fileName, int length)

The parameter “fileName” specifies the file name, and “length” specifies the length of the sequence in the file.

● randomBinaryFile will generate a file containing a sequence of 0 or 1 of the specified length;

● randomNumberFile will generate a file containing a sequence of digits 0, 1, 2, …, 9 of the specified length;

● randomCharFile will generate a file containing a sequence of characters A, B, C, …, Z of the specified length;

Also write a main() method to test your code. In the main() method, you may ask the user to type in a file name, a type of randomness (binary, digit or character), and the length of the file.

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

The following code generates a random character between A and Z:

​​Random r = new Random();​​

​​char a = (char) (r.nextInt(26) + 'A');

Another way is as below:

Random r = new Random();​​

String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

char a = alphabet.charAt(r.nextInt(26));

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// RandomFile.java

import java.io.File;

import java.io.FileNotFoundException;

import java.io.PrintWriter;

import java.util.Random;

import java.util.Scanner;

public class RandomFile {

      // method to generate a file containing random binary values

      public static void randomBinaryFile(String fileName, int length) {

            try {

                  // opening file in write mode

                  PrintWriter writer = new PrintWriter(new File(fileName));

                  // initializing random number generator

                  Random random = new Random();

                  // looping for length times

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

                        // generating a number between (0 or 1) and writing to file.

                        writer.print(random.nextInt(2));

                  }

                  // closing file, saving changes

                  writer.close();

            } catch (FileNotFoundException e) {

                  // invalid file name

                  System.err.println(e);

            }

      }

      // method to generate a file containing random digits

      public static void randomNumberFile(String fileName, int length) {

            try {

                  // opening file in write mode

                  PrintWriter writer = new PrintWriter(new File(fileName));

                  // initializing random number generator

                  Random random = new Random();

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

                        // generating a number between (0 to 9) and writing to file.

                        writer.print(random.nextInt(10));

                  }

                  writer.close();

            } catch (FileNotFoundException e) {

                  System.err.println(e);

            }

      }

      // method to generate a file containing random alphabets

      public static void randomCharFile(String fileName, int length) {

            try {

                  // opening file in write mode

                  PrintWriter writer = new PrintWriter(new File(fileName));

                  // initializing random number generator

                  Random random = new Random();

                  // creating a string of alphabets

                  String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

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

                        // generating an index value between 0 and 25, choosing the

                        // character at that index from alphabet and appending to file.

                        writer.print(alphabet.charAt(random.nextInt(alphabet.length())));

                  }

                  writer.close();

            } catch (FileNotFoundException e) {

                  System.err.println(e);

            }

      }

      public static void main(String[] args) {

            // setting up a Scanner, reading file name, randomness type and length

            Scanner scanner = new Scanner(System.in);

            System.out.print("Enter a filename: ");

            String file = scanner.nextLine();

            System.out

                        .print("Enter type of randomness (b: binary, d: digit or c: character): ");

            char type = scanner.next().toLowerCase().charAt(0);

            System.out.print("Enter length: ");

            int length = scanner.nextInt();

            // based on the chosen type, generating random file. and exiting

            if (type == 'b') {

                  randomBinaryFile(file, length);

            } else if (type == 'd') {

                  randomNumberFile(file, length);

            } else if (type == 'c') {

                  randomCharFile(file, length);

            }

            // this program does not open the file once it is created, you have to

            // check your folder after running this program

      }

}